2020-21 West Central Montana Avalanche upates: 4/29/2021 END OF SEASON PARTING WORDS

[Scott]

Current West Central Montana Avalanche Advisory Posted: Jan 02, 2021 06:45 am Is this email not displaying correctly? View it in your browser.

Avalanche Advisory for January 2, 2021​ View Full Advisory » The avalanche danger in the west central Montana backcountry is MODERATE, with caution. Good morning; this is Jeff Carty with the West Central Montana Avalanche Center’s avalanche advisory for January 2, 2021. This advisory does not apply to operating ski areas, expires at midnight tonight, and is the sole responsibility of the U.S. Forest Service. Weather and Snowpack Mountain temperatures are 18º to 29º F this morning and are forecast to reach the low 30’s today. Up to 3″ of snow has fallen in the last 24 hours. 1″-2″ more is expected today with snowfall continuing through Sunday night. Westerly winds have been moderate with strong gusts and are expected to reach 18mph with gusts to 36 mph today, increasing to 55mph at ridge top this evening. The last round of snowfall deposited between 6” and up to 20” of snow. This bonded well in the areas we toured yesterday, despite widespread surface hoar from the clear nights preceding the storm. However, pockets of reactive unbonded surface hoar likely exist. Wind slab was created but is now bonded well. We couldn’t get any to move yesterday despite crowns from recent natural wind slab avalanches in the Rattlesnake. Our current round of snow will likely not be heavy enough to create problems today. However, winds are creating wind slab problems on steep leeward slopes. Snow intensity will increase tonight and Sunday and avalanche hazard will rise as a result. The underlying snowpack is varied throughout the forecast area. Deeper areas have better bonding and instabilities are isolated to the new snow/old snow interface. The central Bitterroot has been the most stable zone in the past week. In shallow areas, generally under 5 feet in depth, the snowpack structure is still poor. Facets and crust combinations are creating sliding layers. We had propagation in pits with moderate to strong force in the southern Bitterroot, Lolo Pass, and the Rattlesnake yesterday. It is possible to trigger slab avalanches on these layers. They are becoming a low likelihood, high consequence problem. With thicknesses up to 2 feet, these are not slabs to mess with. It’s best to stick to low angle slopes and simple terrain in these areas. The southern Missions and Swans received the brunt of the last storm with 1.6” of snow water equivalent (SWE), up to 20” of snow, a huge load for an area that had faceted snow problems and surface hoar. The northern Swans had a widespread avalanche cycle following the storm. Take care if you are riding in this area and assess slopes carefully. Simple terrain and low angle slopes are good choices as the area receives more snow in the coming days. Bottom Line Windslab will be increasing in size throughout the day, avoid steep wind loaded start zones. Human triggered avalanches are possible. Snow pits and stability tests are essential for identifying the presence of faceted layers and their reactivity. Simple, low angle terrain is advised where persistent slabs exist. Travel one at a time in avalanche terrain, carry a beacon, shovel, and probe. Re-assess conditions throughout the day and stay alert for red flags. Public Observations We generate avalanche forecasts for a 1,420 square mile area that stretches from Lost Trail Pass to just north of Seeley Lake. We work hard to keep you informed of current avalanche dangers but, we can’t see everything. Your snowpack and weather observations help us fill in the gaps and produce a more accurate forecast. If you get out, please take a moment to fill out the online observation form. Ski and ride safe. The post Avalanche Advisory for January 2, 2021 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Jan 05, 2021 06:24 am Is this email not displaying correctly? View it in your browser.

Avalanche Advisory for January 5, 2021​ View Full Advisory » The avalanche danger is CONSIDERABLE today in the west central Montana Backcountry. Winds and new snow are creating dangerous avalanche conditions. Good Morning. This is Travis Craft with the West Central Montana Avalanche Center advisory on Tuesday, January 5th, 2021.This advisory is sponsored by the Trail Head. This advisory does not apply to operating ski areas, expires at midnight tonight, and is the sole responsibility of the U.S. Forest Service. Weather and Snowpack Mountain temperatures range from 22 degrees to 30 degrees F this morning. The advisory area has received 3 to 8 new inches of snow. Winds are ranging from 20 to 30 mph, prime wind speeds for snow transport to leeward slopes. We have a snowpack that is possible to produce avalanches. Pit tests from the Rattlesnake, Lost Trail Pass, and Lolo Pass show that we have weak layers in the top third of the snowpack and near the bottom of our snowpack throughout the advisory area. New snow and winds are putting stress on these layers. This public observation is a great learning experience for all of us on what this snowpack can produce. We are thankful for these people sharing this observation and of the outcome. Bottom Line Look for sheltered, simple low angle terrain today. New snow and winds are stressing our weak layers. Keep it simple today. Avoid wind loaded terrain. Travel one at a time in avalanche terrain, carry a beacon, shovel, and probe. Remember to reassess conditions throughout the day and stay alert for signs of instability. Dig a pit. Look for red flags. Upcoming Education Events: Please visit our education page for an up to date list of regional educational events and course offerings. Below are a few select events and opportunities to check out this week. Wednesday, January 6th, 6–7:30 pm MST, FREE Online 1.5-hr Avalanche Awareness Session | Missoulaavalanche.org + SheJumps event | Delivered by A3 Pro female instructors | Register Here Public Observations Thank you to everyone who has taken the time to send in a public observation. Please keep sharing what you find and see while out in the backcountry. This forum is a great resource to glean information about current conditions. Here is the link to Public Observations. Ski and ride safe. The post Avalanche Advisory for January 5, 2021 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Jan 07, 2021 06:18 am Is this email not displaying correctly? View it in your browser.

Avalanche Advisory for January 7, 2021​ View Full Advisory » The avalanche danger is MODERATE in the west central Montana backcountry today. Human triggered avalanches are possible today. Good Morning. This is Travis Craft with the West Central Montana Avalanche Center advisory on Thursday, January 7th, 2021. This advisory is sponsored by the Trail Head. This advisory does not apply to operating ski areas, expires at midnight tonight, and is the sole responsibility of the U.S. Forest Service. Weather and Snowpack Mountain temperatures range from 22 degrees to 28 degrees F this morning. Winds are primarily calm, gusting to 12 mph out of the West. The forecast area has received 1 to 2 inches of new snow. Warm temperatures yesterday produced roller balls and loose wet slides on sun-exposed slopes to 8000 ft. Pit tests showed that the snowpack is slowly healing and less reactive. There are layers of concern in the top third of the snowpack and in the bottom third. Persistent weak layers are problems that stay with us for a long time. The structure of our snowpack should not be trusted. An unstable result in a pit test plays a large role in my decision-making process, and a stable result plays a small role. Bottom Line Choose simple terrain that does not expose you to terrain traps. Avoid likely trigger points on slopes. Dig a pit and look for stripes in the snow to identify weak layers. Perform a pit test to see how reactive these layers are. Choose a shallow spot to see if you have weak sugary snow at the bottom of the snowpack if you do choose another slope.Travel one at a time in avalanche terrain, carry a beacon, shovel, and probe. Remember to reassess conditions throughout the day and stay alert for signs of instability. Dig a pit. Look for red flags. Upcoming Education Events: Please visit our education page for an up to date list of regional educational events and course offerings. Below are a few select events and opportunities to check out. January 26th-31st | Women’s Avalanche Level 1 Course | Missoulaavalanche.org + SheJumps event | Delivered by A3 Pro female instructors | Get more details and register HERE January 26th-31st | Motorized AIARE 1 Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 6th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 7th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE Public Observations Thank you to everyone who has taken the time to send in a public observation. Please keep sharing what you find and see while out in the backcountry. This forum is a great resource to glean information about current conditions. Here is the link to Public Observations. Ski and ride safe. The post Avalanche Advisory for January 7, 2021 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Jan 09, 2021 06:48 am Is this email not displaying correctly? View it in your browser.

Avalanche Advisory for January 9, 2021​ View Full Advisory » The avalanche danger is MODERATE in the west central Montana backcountry today. Human triggered avalanches are possible today. Good Morning. This is Travis Craft with the West Central Montana Avalanche Center advisory on Thursday, January 09, 2021. This advisory is sponsored by the Trail Head. This advisory does not apply to operating ski areas, expires at midnight tonight, and is the sole responsibility of the U.S. Forest Service. Weather and Snowpack Mountain temperatures range from 19 degrees to 26 degrees F this morning. Winds are primarily calm. The forecast area has received no new snow. There is a lot of variability in our snowpack in the advisory area. High in the central Bitterroot above 8000 ft, is 5 to 6 feet deep. Elevations below 8000 ft you can find snowpack depths of two feet on south slopes that are faceting and creating depth hoar where you get off your skis or machine and punch to the ground. You can find a layer of buried surface hoar in the top third of the snowpack that is reactive in pit tests, and in some places, this layer is not as reactive. There are facets in shallow snowpacks (less than 4 feet deep) near the ground propagating in pit tests. The overall take-home point is there is a lot of variability in the depth and distribution of layers of concern. This snowpack is one not to try to outthink. Persistent weak layers are very unpredictable. You can be the first person on a slope and trigger the avalanche, or you may be the 10th person on a slope and hit the trigger point. Here is a video. I like to think of avalanche problems as dragons. The size of the avalanche equals the size of the dragon. How likely I trigger the avalanche means how likely I awake the dragon living in its snow cave. For example, 5 new inches of snow have fallen and there are no persistent weak layers in the snowpack. The only dragons I have today are loose snow sluffs. I will wake these dragons, but they are small baby dragons, and I can manage them. Our snowpack has multiple dragons(video) (video) A layer of buried surface hoar in the upper third of the snowpack. If I wake this dragon up, it could bury and kill me. The other dragon is the facets near the ground in shallow snowpacks. It is harder to wake this dragon but this dragon is big and if I wake it up, it will bury and kill me. Bottom Line To avoid waking dragons up, stick to simple low angle slopes. Slopes less than 30 degrees are less likely to produce avalanches. Choose simple terrain that does not expose you to terrain traps. Avoid likely trigger points on slopes. Dig a pit and look for stripes in the snow to identify weak layers. Perform a pit test to see how reactive these layers are. Choose a shallow spot to see if you have weak sugary snow at the bottom of the snowpack; if you do, choose another slope. I do not trust the structure of the snowpack. An unstable result in a pit test plays a large role in my decision-making process, and a stable result plays a small part. Travel one at a time in avalanche terrain, carry a beacon, shovel, and probe. Remember to reassess conditions throughout the day and stay alert for signs of instability. Dig a pit. Look for red flags. Upcoming Education Events: Please visit our education page for an up to date list of regional educational events and course offerings. Below are a few select events and opportunities to check out. January 26th-31st | Women’s Avalanche Level 1 Course | Missoulaavalanche.org + SheJumps event | Delivered by A3 Pro female instructors | Get more details and register HERE January 26th-31st | Motorized AIARE 1 Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 6th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 7th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE Public Observations Thank you to everyone who has taken the time to send in a public observation. Please keep sharing what you find and see while out in the backcountry. This online forum is a great resource to glean information about current conditions. Remember, you can submit your observations through the observation page anonymously. When submitted anonymously, the forecasters review the observation and utilize it when generating the forecast. The information does not appear on the public observation page. Ski and ride safe. The post Avalanche Advisory for January 9, 2021 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Jan 12, 2021 06:45 am Is this email not displaying correctly? View it in your browser.

Avalanche Advisory for January 12, 2021​ View Full Advisory » MODERATE avalanche danger will rise to CONCIDERABLE in the west central Montana backcountry today with the arrival of the storm. Good Morning. This is Jeff Carty with the West Central Montana Avalanche Center advisory on Tuesday, January 12th, 2021. This advisory is sponsored by LB Snow. This advisory does not apply to operating ski areas, expires at midnight tonight, and is the sole responsibility of the U.S. Forest Service. Weather and Snowpack Mountain temperatures range from 24 º to 35º F this morning. Winds are moderate. The advisory area has received no new snow. We are on track for an atmospheric river to pass over us today and tomorrow. Up to 9″ of snow, the potential for rain above 5000’ and winds to 43mph are forecast today. Up to 3” of SWE are expected by tomorrow night. Avalanche hazard will increase with the storm. Of particular concern is the effect of warm temps, heavy snow, and rain on mid-elevations where the snowpack has the worst structure. Wind slab will be growing throughout the day as well. Widespread surface hoar will likely create problems once the storm deposits enough snow to create a slab. Variable is the best way to describe the snowpack throughout the forecast area. Minutely variable. Wide-ranging conditions can be found in very close proximity making stability assessments challenging. Yesterday at Gash Point the 6’ deep snowpack at 7300’ on the north aspect was well consolidated with no concerning layers. 500’ lower at 6800’ on the same aspect the snowpack was 3’ deep, comprised entirely of facets. It has truly terrible structure that cannot be trusted. Shallow mid-elevation and wind-scoured areas have similar faceting throughout the forecast area. In the southern Missions yesterday, a small human triggered avalanche ran on buried surface hoar, but extended column tests (ECT) adjacent to the slide were not propagating. A similar buried surface hoar problem exists throughout the forecast area. The north aspect of Mt. Fuji over the weekend was showing increased strength and consolidation, while the south face has developed depth hoar and failing in tests. In the southern Bitterroot yesterday, small wind slabs were touchy, and faceted layers remain a concern. What this means is you need to be really heads up. Deeper faceted layers will not give warning signs if they fail. Slight changes of aspect and elevation can result in drastically different snowpack and stability. One pit and stability test will not suffice to give you a good handle on problem layers. The best way to deal with the myriad of current problems is to investigate the snowpack often and only commit to lines if you can be certain of the distribution of problem layers. Avoid anything with soft facets or propagation. As the storm roles in today dial it back to low angle slopes. The Rattlesnake may have the shallowest snowpack in the area and as a result the worst structure. Some spots are touchier than others but the whole zone requires caution. Staying under 30º is wise. Assessing instability in facets can be challenging, and it is easy to fall into decision making traps, especially if it is a problem you are unfamiliar with. Please see this extended column test refresher for some tips. The Bottom Line Stability will deteriorate with snow, wind, rising temperatures, and potentially rain at mid-elevations today. Avalanches will become likely. Various facet, surface hoar, and windslab layers exist throughout the snowpack. In some places, depth hoar and advanced facets are low likelihood/ high consequence problems. Careful, and frequent snowpack assessment is required with the variable snowpack. Sticking to lower angle slopes is the best plan. Expect the avalanche hazard to rise Wednesday. Travel one at a time in avalanche terrain, carry a beacon, shovel, and probe. Remember to reassess conditions throughout the day and stay alert for signs of instability. Dig a pit. Look for red flags. Upcoming Education Events: Please visit our education page for an up to date list of regional educational events and course offerings. Below are a few select events and opportunities to check out. Wednesday, January 13th, 6–7:30 PM MST | FREE Online 1.5-hr Avalanche Awareness Session | Missoulaavalanche.org Virtual Webcast | Delivered by A3 Pro instructors | Get more details and register HERE January 26th-31st | Women’s Avalanche Level 1 Course | Missoulaavalanche.org + SheJumps event | Delivered by A3 Pro female instructors | Get more details and register HERE January 26th-31st | Motorized AIARE 1 Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 6th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 7th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE

 

[Scott]

Continued from Jan 12:

Public Observations Thank you to everyone who has taken the time to send in a public observation. Please keep sharing what you find and see while out in the backcountry. This online forum is a great resource to glean information about current conditions. Remember, you can submit your observations through the observation page anonymously. When submitted anonymously, the forecasters review the observation and utilize it when generating the forecast. The information does not appear on the public observation page. Ski and ride safe.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Jan 12, 2021 07:01 pm Is this email not displaying correctly? View it in your browser.

Avalanche Warning for January 12, 2021​ View Full Advisory » An avalanche warning has been issued for the southern Mission, southern Swan, Rattlesnake, and southern and central Bitterroot mountains. The avalanche danger for the west central Montana backcountry is HIGH. The avalanche hazard is increasing with continued snowfall, rising temperatures, wind, and rain. Human triggered avalanches are certain. Avalanches may run long distances. Travel in avalanche terrain is not recommended. This avalanche warning is valid for 24 hours. The avalanche warning will either be extended or terminated at 7:00 pm on January 13, 2021. This danger rating does not apply to operating ski areas and is the sole responsibility of the U.S. Forest Service. Continued snow and wind will accompany rising temperatures with freezing levels climbing up to 8000′ and rain to 7000′ by Wednesday morning. Up to 3” of SWE is expected by tomorrow night. Avalanche hazard will increase with the storm. Of particular concern is the effect of warm temps, heavy snow, and rain on mid-elevations where the snowpack has the worst structure. Wind slab will be growing. Widespread surface hoar under the new snow is an issue. Natural avalanches are likely, human triggered avalanches are certain. Variable is the best way to describe the snowpack throughout the forecast area. Minutely variable. Wide-ranging conditions can be found in very close proximity making stability assessments challenging. Yesterday at Gash Point the 6’ deep snowpack at 7300’ on the north aspect was well consolidated with no concerning layers. 500’ lower at 6800’ on the same aspect the snowpack was 3’ deep, comprised entirely of facets. It has truly terrible structure that cannot be trusted. Shallow mid-elevation and wind-scoured areas have similar faceting throughout the forecast area. In the southern Missions yesterday, a small human triggered avalanche ran on buried surface hoar. A similar problem exists throughout the forecast area. The north aspect of Mt. Fuji over the weekend was showing increased strength and consolidation, while the south face has developed depth hoar and failing in tests. In the southern Bitterroot yesterday, small wind slabs were touchy, and faceted layers remain a concern. The Rattlesnake may have the shallowest snowpack in the area and as a result the worst structure. Some spots are touchier than others but the whole zone requires caution. Staying under 30º is wise. Throughout the forecast area there was widespread surface hoar prior to this storm. Heavy snow and wind are rapidly loading all of these layers and problems. Warm temperatures are loosening bonds within the snowpack. Rain may further deteriorate stability. The Bottom Line Travel in avalanche terrain is not recommended. Avoid runout zones. You can trigger an avalanche remotely. This warning will be terminated or extended tomorrow at 7:00 pm. Ski and ride safe. The post Avalanche Warning for January 12, 2021 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Jan 14, 2021 06:55 am Is this email not displaying correctly? View it in your browser.

Avalanche Advisory for January 14, 2021​ View Full Advisory » The avalanche in the west central Montana backcountry is HIGH in wind loaded terrain above 7000′ and CONSIDERABLE in all other terrain. Good Morning. This is Jeff Carty with the West Central Montana Avalanche Center advisory on Thursday, January 14th, 2021. This advisory is sponsored by LB Snow. This advisory does not apply to operating ski areas, expires at midnight tonight, and is the sole responsibility of the U.S. Forest Service. Weather and Snowpack Mountain temperatures range from 15º to 23º F this morning. Winds are moderate out of the west. The advisory area has received no new snow overnight except for Twin lakes in the central Bitterroot that received o.6″ of snow water equivalent (SWE). It’s been an eventful 48 hours. Stuart SNOTEL in the Rattlesnake reported a total of 2.2″ SWE, a massive load for the weakest snowpack in the forecast area. Winds reached 125mph on Mt. Sentinel, the Swans saw winds of 65mph and gusts to 101mph and, Lolo Pass had winds to 106mph. Temperatures reached 39ºF at 6400′ at Twin lakes and 34ºF at 7400′ on Stuart. Rain reached at least 7400′ in elevation. Above 7600′ in the central Bitterroot, there was up to 14″ of new snow. Skiing and riding conditions below the rain line were poor. A stout crust will be around for a while. Conditions continue to be highly variable. We are forecasting today for the most unstable spots in the forecast area. Pockets of more stability may exist, however, the extent of the wind, loading, and number of natural avalanches observed yesterday warrant a cautious rating. It will take a couple of days to see what the extent of the natural avalanche cycle was and how the snowpack throughout the forecast area is responding to the new load. During that time it is wise to recreate on lower angle slopes. There was a lot of variance in what the storm produced. Yesterday in Crystal Amphitheater, 6″ of wet snow, capped with a crust, sat on top of the old snow. Under the new snow, surface hoar was still present and reactive in compression tests but the overlying slab was not stiff enough to propagate yet. Below this the snow was dry, moisture had not inundated the snowpack despite rain to 7400′. In Bass Creek, at 7000′, the snowpack was saturated to the ground and without evidence of natural avalanches. On the west side of the Bitterroot Crest, a widespread natural avalanche cycle had occurred. Windslab was failing naturally and propagating long distances, wrapping around terrain features. In many areas, where the snowpack was saturated, persistent weak layers should stabilize with freezing. In others where the water did not penetrate the snowpack, persistent weak layers may continue to be an issue. Surface hoar from before this storm could still be lurking and reactive both above and below the rain line. What this means is you need to be heads up. Slight changes of aspect and elevation can still result in drastically different snowpack and stability. One pit and stability test will not suffice to give you a good handle on problem layers. The best way to deal with the myriad of current problems is to investigate the snowpack often. Windslab is the biggest concern at higher elevations where abundant new snow is available for transport and there have been 48hrs of sustained wind. The Bottom Line Dangerous avalanche conditions exist, travel in avalanche terrain is not recommended. The snowpack has been rapidly loaded and how it is reacting throughout the forecast area is not yet clear. It’s best to give it a couple of days after this storm to settle out. It is certain to trigger wind slabs in steep upper elevation terrain. Avoid wind loaded slopes higher than 7000′. Travel one at a time in avalanche terrain, carry a beacon, shovel, and probe. Remember to reassess conditions throughout the day and stay alert for signs of instability. Dig a pit. Look for red flags. Upcoming Education Events: Please visit our education page for an up to date list of regional educational events and course offerings. Below are a few select events and opportunities to check out. January 20th, 6-7:30 PM MST | FREE Online 1.5-hr Avalanche Awareness Session | Missoulaavalanche.org + SheJumps event | Delivered by A3 Pro female instructors | Get more details and register HERE January 26th-31st | Women’s Avalanche Level 1 Course | Missoulaavalanche.org + SheJumps event | Delivered by A3 Pro female instructors | Get more details and register HERE January 26th-31st | Motorized AIARE 1 Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 6th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 7th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE

 

[Scott]

Continued from Jan 14 report:

Public Observations
Thank you to everyone who has taken the time to send in a public observation. Please keep sharing what you find and see while out in the backcountry. This online forum is a great resource to glean information about current conditions.
Remember, you can submit your observations through the observation page anonymously. When submitted anonymously, the forecasters review the observation and utilize it when generating the forecast. The information does not appear on the public observation page.
Ski and ride safe.

The post Avalanche Advisory for January 14, 2021 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Jan 19, 2021 06:15 am Is this email not displaying correctly? View it in your browser.

Avalanche Advisory for January 19, 2021​ View Full Advisory » The avalanche danger is MODERATE in the west central Montana backcountry today. Human triggered avalanches are possible today. Good Morning. This is Travis Craft with the West Central Montana Avalanche Center advisory on Tuesday, January 19th, 2021. This advisory is sponsored by LB Snow. This advisory does not apply to operating ski areas and expires at midnight tonight. The USDA Forest Service is solely responsible for its content. Weather and Snowpack Mountain temperatures range from 11 degrees to 22 degrees F this morning. Winds are primarily calm today. The advisory area received no new snow overnight. The snowpack is drastically different from drainage to drainage. This is spatial variability. Yesterday, a skier triggered a slide on Saddle Mountain by hitting the sweet spot on a cornice. The crown was 75′ wide and 1-2 feet deep on a 40-degree starting zone. The slide ran 500 ft of the 1500 ft path stopping in lower angle terrain. In the Rattlesnake, weak layers are propagating in pit tests. In the Lost Horse drainage, weak layers are not propagating but are still present. Gash Point, there are wind slabs at 8000 ft that are easily triggered and in lower elevations, widespread collapsing on buried weak layers. The rain crust seems to peter out around 7500 ft throughout the advisory area. The definition of moderate danger is HEIGHTENED AVALANCHE CONDITIONS ON SPECIFIC TERRAIN FEATURES. EVALUATE SNOW AND TERRAIN CAREFULLY; IDENTIFY FEATURES OF CONCERN. What does this mean for our snowpack? Look for signs of wind loading. Dig multiple pits as you change elevation and aspect. Choose sheltered lower angle terrain to get a feel for the snow. Use hand pits and small test slopes to get a picture of the snow. Bottom Line Today, choose sheltered lower angle slopes. Avoid slopes with weak sugary snow. Do multiple pits investigating the stripes in your pit wall. Avoid cornices and wind loaded terrain. Choose simple terrain that does not expose you to terrain traps. Avoid likely trigger points on slopes. Travel one at a time in avalanche terrain, carry a beacon, shovel, and probe. Remember to reassess conditions throughout the day and stay alert for signs of instability. Dig a pit. Look for red flags. Upcoming Education Events: Please visit our education page for an up to date list of regional educational events and course offerings. Below are a few select events and opportunities to check out. January 20th, 6-7:30 PM MST | FREE Online 1.5-hr Avalanche Awareness Session | Missoulaavalanche.org + SheJumps event | Delivered by A3 Pro female instructors | Get more details and register HERE January 26th-31st | Motorized AIARE 1 Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 6th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 7th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE Public Observations Thank you to everyone who has taken the time to send in a public observation. Please keep sharing what you find and see while out in the backcountry. This online forum is a great resource to glean information about current conditions. Remember, you can submit your observations through the observation page anonymously. When submitted anonymously, the forecasters review the observation and utilize it when generating the forecast. The information does not appear on the public observation page. Ski and ride safe. The post Avalanche Advisory for January 19, 2021 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Jan 21, 2021 06:09 am Is this email not displaying correctly? View it in your browser.

Avalanche Advisory for January 21, 2021​ View Full Advisory » The avalanche danger is MODERATE in the west central Montana backcountry today. Human triggered avalanches are possible today. Good Morning. This is Travis Craft with the West Central Montana Avalanche Center advisory on Tuesday, January 21st, 2021. This advisory is sponsored by LB Snow. This advisory does not apply to operating ski areas and expires at midnight tonight. The USDA Forest Service is solely responsible for its content. Weather and Snowpack Mountain temperatures range from 18 degrees to 25 degrees F this morning. Winds are 4 mph gusting to 8 mph out of the West. The advisory area received no new snow overnight. Persistent weak layers in the snowpack and wind drifted snow are the main avalanche problems. The likelihood of triggering an avalanche is decreasing slowly. It is still possible to trigger a wind slab on steeper slopes greater than 35 degrees at higher elevations near ridges. Cornices are getting large and getting weaker. The persistent weak layers are less reactive in pit tests. We could get facets below the rain crust from 01/13/2021 to propagate yesterday in the Lolo Pass area. In drainages in the central Bititterroot and Sweeny, this layer did not propagate. The buried surface hoar layers deeper in the snowpack (2 feet) are becoming less and less likely triggered. Overall we are gaining strength in the snowpack. The shallowest snowpack in the forecast area is the Rattlesnake. There are still many shallow spots on slopes where triggering these weak layers is possible. The places to avoid on slopes are near cliff bands, rocks, and roll overs. These areas will have shallower snowpacks. Terrain choice is the only option to reduce our exposure to avalanches. ATES is a way to describe terrain using the definitions simple, challenging, and complex. Here is a link to help understand the terminology and ranking. Looking at today’s avalanche problems I would choose simple terrain. Then after evaluating the snowpack with multiple pit tests and avoiding steep wind-loaded start zones, slowly ease into challenging terrain. This builds in safety margins. Bottom Line Today, choose sheltered lower angle slopes. Avoid slopes with weak sugary snow. Do multiple pits investigating the stripes in your pit wall. Avoid cornices and wind loaded terrain. Choose simple terrain that does not expose you to terrain traps. Avoid likely trigger points on slopes. Travel one at a time in avalanche terrain, carry a beacon, shovel, and probe. Remember to reassess conditions throughout the day and stay alert for signs of instability. Dig a pit. Look for red flags. Upcoming Education Events: Please visit our education page for an up to date list of regional educational events and course offerings. Below are a few select events and opportunities to check out. January 26th-31st | Motorized AIARE 1 Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 6th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 7th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE Public Observations Thank you to everyone who has taken the time to send in a public observation. Please keep sharing what you find and see while out in the backcountry. This online forum is a great resource to glean information about current conditions. Remember, you can submit your observations through the observation page anonymously. When submitted anonymously, the forecasters review the observation and utilize it when generating the forecast. The information does not appear on the public observation page. Ski and ride safe. The post Avalanche Advisory for January 21, 2021 appeared first on Missoula Avalanche. This information is the sole responsibility of the Forest Service and does not apply to operating ski areas. The avalanche danger rating expires at midnight tonight but you can use the information we provide to help you make more informed decisions regarding travel in avalanche terrain for the next few days. Our advisory area includes the Bitterroot Mountains from Lost Trail Pass North to Hoodoo Pass, the Rattlesnake Mountains and the Southern Swan and Mission Mountains near Seeley Lake. Avalanche information for the Lookout Pass/St. Regis Basin is available from the Idaho Panhandle Avalanche Center.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Jan 23, 2021 06:15 am Is this email not displaying correctly? View it in your browser.

Avalanche Advisory for January 23, 2021​ View Full Advisory » The avalanche danger is MODERATE in the Rattlesnake and LOW in the central and southern Bitterroot, and Seeley Lake zone. It is possible to trigger an avalanche in the Rattlesnake. There are isolated avalanche problems in the other zones. Low does not mean no avalanche danger. Good Morning. This is Travis Craft with the West Central Montana Avalanche Center advisory on Saturday, January 23rd, 2021. This advisory is sponsored by LB Snow. This advisory does not apply to operating ski areas and expires at midnight tonight. The USDA Forest Service is solely responsible for its content. Weather and Snowpack Mountain temperatures range from 13 degrees to 22 degrees F this morning. No new snow overnight. The snowpack is gaining strength throughout most of the region. Shallow snowpacks( 3 feet deep) are the weakest. You can find these shallow points in lower elevations and throughout the Rattlesnake. Yesterday, we saw small point releases in Lolo, St Mary’s, Seeley Lake area, and the Rattlesnake. The Jan 13 rain crust is the layer to investigate before committing to avalanche terrain. There are facets below the crust that are sometimes reactive in pit tests. The Rattlesnake has the weakest, shallowest snowpack. The weak structure in the Rattlesnake is creating Moderate avalanche danger. Today, I would choose simple, low angle slopes and avoid slopes with shallow snowpacks in the Rattlesnake. In the rest of the advisory area, I would avoid wind-loaded terrain, choose simple slopes, and then work into more complicated terrain. The places to avoid on slopes are near cliff bands, rocks, and rollovers. These areas will have shallower snowpacks where it more likely to trigger an avalanche. Bottom Line Today, do your homework before committing to steep slopes. Avoid slopes with weak sugary snow. Do multiple pits investigating the stripes in your pit wall. Avoid cornices and wind loaded terrain. Choose simple terrain that does not expose you to terrain traps. Avoid likely trigger points on slopes. Travel one at a time in avalanche terrain, carry a beacon, shovel, and probe. Remember to reassess conditions throughout the day and stay alert for signs of instability. Dig a pit. Look for red flags. Upcoming Education Events: Please visit our education page for an up to date list of regional educational events and course offerings. Below are a few select events and opportunities to check out. January 26th-31st | Motorized AIARE 1 Course | Delivered by the Mountain Riding Lab | Get more details and register HERE January 27th, 6-7:30 PM MST | FREE Online 1.5-hr Avalanche Awareness Session | Missoulaavalanche.org event | Delivered by A3 Pro instructors | Get more details and register HERE February 6th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 7th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE Public Observations Thank you to everyone who has taken the time to send in a public observation. Please keep sharing what you find and see while out in the backcountry. This online forum is a great resource to glean information about current conditions. Remember, you can submit your observations through the observation page anonymously. When submitted anonymously, the forecasters review the observation and utilize it when generating the forecast. The information does not appear on the public observation page. Ski and ride safe. The post Avalanche Advisory for January 23, 2021 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Jan 26, 2021 06:46 am Is this email not displaying correctly? View it in your browser.

Avalanche Advisory for January 26, 2021​ View Full Advisory » The avalanche danger is MODERATE in the Rattlesnake and LOW in the central and southern Bitterroot, and Seeley Lake zone. It is possible to trigger an avalanche in the Rattlesnake. There are isolated avalanche problems in the other zones. Low does not mean no avalanche danger. Good Morning. This is Jeff Carty with the West Central Montana Avalanche Center advisory on Tuesday, January 26th, 2021. This advisory is sponsored by the Rocky Mountaineers. This advisory does not apply to operating ski areas and expires at midnight tonight. The USDA Forest Service is solely responsible for its content. Weather and Snowpack Mountain temperatures range from 13 degrees to 22 degrees F this morning. No new snow overnight. Winds are light and southerly. Low hazard is defined as: Generally safe avalanche danger, watch for unstable snow on isolated terrain features. This is what we have throughout the majority of our forecast area. Overall it is unlikely to trigger an avalanche. However, due to spatial variability diligent hazard assessment is required despite the low rating. Suspect areas are shallow snowpacks, generally under 4 feet in depth, where persistent weak layers exist. These can be found at mid elevations and on wind scoured slopes. Upper elevation leeward slopes may contain wind slab. Cornices have been growing and are a hazard. Terrain traps will increase the consequences of these problems. The exception to the low rating is the Rattlesnake, where there is moderate hazard. This range has received less snow than the rest of the forecast area and as a result the structure has been slowly deteriorating due to the growth of facets and depth hoar. These layers are stubborn and deep. While it is not likely to trigger these layers, it is possible. Given the depth and stiffness of the slab, the resulting avalanche could be very destructive. Layers such as this can be tricky to assess. As persistent weak layers get buried deeper, they become unpredictable. They will likely not give warning signs such as cracking or whumphing, can avalanche despite being skied repeatedly, and as they get deeper can produce false stable results on extended column tests. The propagation saw test is a good test for deep faceted layers if you are not seeing propagation in the ECT. The best approach is to avoid slopes over 30º. Bottom Line Generally stable conditions exist, except in the Rattlesnake where it is possible to trigger an avalanche. Due to spatial variability, isolated instabilities are present throughout the forecast area. Avoid slopes with weak sugary snow. Do multiple pits investigating the stripes in your pit wall. Avoid cornices and wind loaded terrain. Choose simple terrain that does not expose you to terrain traps. Avoid likely trigger points on slopes. Travel one at a time in avalanche terrain, carry a beacon, shovel, and probe. Remember to reassess conditions throughout the day and stay alert for signs of instability. Dig a pit. Look for red flags. Upcoming Education Events: Please visit our education page for an up to date list of regional educational events and course offerings. Below are a few select events and opportunities to check out. January 27th, 6-7:30 PM MST | FREE Online 1.5-hr Avalanche Awareness Session | Missoulaavalanche.org event | Delivered by A3 Pro instructors | Get more details and register HERE January 28th-31st | Motorized AIARE 1 Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 6th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 7th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE Public Observations Thank you to everyone who has taken the time to send in a public observation. Please keep sharing what you find and see while out in the backcountry. This online forum is a great resource to glean information about current conditions. Remember, you can submit your observations through the observation page anonymously. When submitted anonymously, the forecasters review the observation and utilize it when generating the forecast. The information does not appear on the public observation page. Ski and ride safe. The post Avalanche Advisory for January 26, 2021 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Jan 28, 2021 06:45 am Is this email not displaying correctly? View it in your browser.

Avalanche Advisory for January 28, 2021​ View Full Advisory » The avalanche danger is MODERATE in the Rattlesnake and LOW in the central and southern Bitterroot, and Seeley Lake zone. It is possible to trigger an avalanche in the Rattlesnake. There are isolated avalanche problems in the other zones. Low does not mean no avalanche danger. Good Morning. This is Jeff Carty with the West Central Montana Avalanche Center advisory on Thursday, January 28th, 2021. This advisory is sponsored by the Rocky Mountaineers. This advisory does not apply to operating ski areas and expires at midnight tonight. The USDA Forest Service is solely responsible for its content. Weather and Snowpack Mountain temperatures range from 18º to 28º F this morning. Some areas in the Bitterroot picked up 0.1″-0.3″ SWE in the last 24h. Winds are southerly and light with moderate gusts, blowing harder at ridge top in the Swans. Not much has changed throughout the forecast area. Surface hoar and near surface facets have developed and will be an issue if we get a load of snow on top of them. The wind picked up a bit and transported snow to leeward aspects. Low hazard is defined as: Generally safe avalanche danger, watch for unstable snow on isolated terrain features. This is what we have throughout the majority of our forecast area. Overall it is unlikely to trigger an avalanche. However, due to spatial variability, isolated instabilities are present. Diligent hazard assessment is required despite the low rating. Suspect areas are shallow snowpacks, generally under 4 feet in depth, where persistent weak layers exist. These can be found at mid elevations and on wind scoured slopes. Upper elevation leeward slopes may contain wind slab. Cornices have been growing and are a hazard. Terrain traps will increase the consequences of these problems. The exception to the low rating is the Rattlesnake, where there is moderate hazard. This range has received less snow than the rest of the forecast area and as a result, the structure has been slowly deteriorating due to the growth of facets and depth hoar. These layers are stubborn and deep. We were still finding propagation on multiple layers yesterday in the Rattlesnake, indicating that the problem is not going away. See this video. While it is not likely to trigger these layers, it is possible. Given the depth and stiffness of the slab, the resulting avalanche could be very destructive. Layers such as this can be tricky to assess. As persistent weak layers get buried deeper, they become unpredictable. They will likely not give warning signs such as cracking or whumphing, can avalanche despite being skied repeatedly, and as they get deeper can produce false stable results on extended column tests. The propagation saw test is a good test for deep faceted layers if you are not seeing propagation in the ECT. The best approach is to avoid slopes over 30º. Bottom Line Generally stable conditions exist, except in the Rattlesnake where it is possible to trigger an avalanche. Due to spatial variability, isolated instabilities are present throughout the forecast area. Avoid slopes with weak sugary snow. Do multiple pits investigating the stripes in your pit wall. Avoid cornices and wind loaded terrain. Choose simple terrain that does not expose you to terrain traps. Avoid likely trigger points on slopes. Travel one at a time in avalanche terrain, carry a beacon, shovel, and probe. Remember to reassess conditions throughout the day and stay alert for signs of instability. Dig a pit. Look for red flags. Upcoming Education Events Please visit our education page for an up to date list of regional educational events and course offerings. Below are a few select events and opportunities to check out. February 6th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 7th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE Public Observations Thank you to everyone who has taken the time to send in a public observation. Please keep sharing what you find and see while out in the backcountry. This online forum is a great resource to glean information about current conditions. You can now text us your observations to (406) 219-5566 when you don’t have time to fill out the observations page. Texted observations won’t get posted on the website, but will be used in the development of the forecast. Ski and ride safe. The post Avalanche Advisory for January 28, 2021 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Jan 30, 2021 06:48 am Is this email not displaying correctly? View it in your browser.

Avalanche Advisory for January 30, 2021​ View Full Advisory » The avalanche danger is MODERATE in the Rattlesnake and southern Bitterroot and LOW in the central Bitterroot, Lolo, and Seeley Lake zone. Low danger does not mean no avalanche danger, isolated instabilities exist. Good Morning. This is Jeff Carty with the West Central Montana Avalanche Center advisory on Saturday, January 30th, 2021. This advisory is sponsored by the Rocky Mountaineers. This advisory does not apply to operating ski areas and expires at midnight tonight. The USDA Forest Service is solely responsible for its content. Weather and Snowpack A bit of snow trickled in, 1-3” in most areas, but up to 12″ the southern Bitterroot. Winds have been relatively mild and westerly. Mountain temperatures this morning are 20ºF to 29ºF. Freezing temps rose to around 6000’ yesterday bringing heavy snow to lower elevations. The southern Bitterroot won this round of snowfall with 10″ to 12” in the last 72hrs. It fell on widespread surface hoar. Tests were showing low strength yesterday, but not propagation. However, it was collapsing and cracking during travel. As the new snow consolidates into a slab it may transmit propagation further. Avalanches are possible and the hazard is moderate in the southern Bitterroot. Restricting travel to slopes under 30º is advised until the reactivity of the new snow is clear. Watch for collapsing and cracking, and propagation in stability tests. The Rattlesnake remains at moderate hazard. The snowpack structure in this range has been slowly deteriorating due to the growth of facets and depth hoar. North and east aspects have the most concerning structure, but all aspects have issues. Collapsing and cracking yesterday on two different aspects and elevations are indicative of weak trigger points that could initiate propagation and result in avalanches if the slope is steep enough. While it is not likely to trigger these layers, it is possible. Given the depth and stiffness of the slab, the resulting avalanche could be very destructive. Layers such as this can be tricky to assess. As persistent weak layers get buried deeper, they become unpredictable. They may not give warning signs such as cracking or whumphing, can avalanche despite being skied repeatedly, and as they get deeper can produce false stable results on extended column tests. The propagation saw test is a good second test for deep faceted layers if you are not seeing propagation in the ECT. The best approach is to avoid slopes over 30º. Elsewhere in the forecast area, there has been minimal change, and avalanche hazard is low. The bit of new snow was nice for a light refresh but was not enough to cause avalanche concerns. In certain areas, it may have been transported to leeward aspects, but wind slab will remain small and isolated. Overall it is unlikely to trigger an avalanche. However, due to spatial variability, isolated instabilities are present. For instance, we found propagation in low strength near surface facets under the rain crust on a north aspect at 6800’ in Bass Creek yesterday. Diligent hazard assessment is required despite the low rating. Suspect areas are shallow snowpacks, generally under 4 feet in depth, where persistent weak layers exist. These can be found at mid elevations and on wind scoured slopes. Cornices have been growing and are a hazard, there was evidence of cornice fall in Bass Creek yesterday. Terrain traps will increase the consequences of these problems. Bottom Line In the southern Bitterroot, avalanches are possible due to 12” of new snow overlying surface hoar. In the Rattlesnake, it is possible to trigger an avalanche on faceted snow. Elsewhere in the forecast area generally stable conditions exist. Due to spatial variability, isolated instabilities are present. Avoid slopes with weak sugary snow. Do multiple pits investigating the layers in your pit wall. Avoid cornices and wind loaded terrain. Choose simple terrain that does not expose you to terrain traps. Avoid likely trigger points on slopes. Travel one at a time in avalanche terrain, carry a beacon, shovel, and probe. Remember to reassess conditions throughout the day and stay alert for signs of instability. Dig a pit. Look for red flags. Upcoming Education Events February 6th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 7th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE Public Observations Thank you to everyone who has taken the time to send in a public observation. Please keep sharing what you find and see while out in the backcountry. This online forum is a great resource to glean information about current conditions. You can now text us your observations to (406) 219-5566 when you don’t have time to fill out the observations page. Texted observations won’t get posted on the website, but will be used in the development of the forecast. Ski and ride safe. The post Avalanche Advisory for January 30, 2021 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Feb 02, 2021 06:10 am Is this email not displaying correctly? View it in your browser.

Avalanche Advisory for February 2, 2021​ View Full Advisory » The avalanche danger is MODERATE in the west central Montana Backcountry today. Good Morning. This is Travis Craft with the West Central Montana Avalanche Center advisory on Tuesday, February 2nd, 2021. This advisory is sponsored by the Big Sky Brewing Company. This advisory does not apply to operating ski areas and expires at midnight tonight. The USDA Forest Service is solely responsible for its content. Weather and Snowpack Mountain temperatures range from 25 degrees to 38 degrees F this morning. 0 to 2 inches of new snow fell in the last 24 hours. Winds are 15 mph gusting into the 30’s out of the SSW. Rising temperatures and gusty winds are elevating avalanche danger this morning. The snow line is expected to be around 5000 ft to 5500 ft. Winds will transport snow to leeward slopes creating wind slabs. At mid-elevations, expect to see loose wet snow problems with a rain-snow mix. Roller balls indicate the snow surfaces are losing strength. Rain and new snow will be testing weak layers in the snowpack depending on elevations. We have seen the snowpack gain strength in the last couple of days, with very few pit scores trending towards instability. Shallower snowpacks have shown instabilities with collapsing and snow sliding out on skin tracks later in the day in mid-elevations. Today is a weather change, avalanche danger will increase throughout the day. Keep the terrain simple today. Avoid wind loaded areas near ridges and start zones. Glide cracks are beginning to appear in different areas. These are unpredictable and should be avoided. Cornices are quite large and should be given a wide berth with rising temperatures and increased winds. Roller balls are signs of wet avalanche problems developing and mean it is time to head home. The new addition of weight to the snowpack will test the facets in our snowpack. Snow at higher elevations will be falling on a variety of old snow surfaces. Use small test slopes and hand pits to see how the new snow is bonding to these surfaces. Keep the terrain simple and low angle. Bottom Line Avoid slopes with weak sugary snow. Do multiple pits investigating the layers in your pit wall. Avoid cornices and wind loaded terrain. Choose simple terrain that does not expose you to terrain traps. Avoid likely trigger points on slopes. Travel one at a time in avalanche terrain, carry a beacon, shovel, and probe. Remember to reassess conditions throughout the day and stay alert for signs of instability. Dig a pit. Look for red flags. Upcoming Education Events: Please visit our education page for an up to date list of regional educational events and course offerings. Below are a few select events and opportunities to check out. February 6th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE February 7th | Motorized Avalanche Rescue Course | Delivered by the Mountain Riding Lab | Get more details and register HERE Public Observations Thank you to everyone who has taken the time to send in a public observation. Please keep sharing what you find and see while out in the backcountry. This online forum is a great resource to glean information about current conditions. You can now text us your observations to (406) 219-5566 when you don’t have time to fill out the observations page. Texted observations won’t get posted on the website, but will be used in the development of the forecast. Ski and ride safe. The post Avalanche Advisory for February 2, 2021 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Feb 04, 2021 06:33 am Is this email not displaying correctly? View it in your browser.

Avalanche Advisory for February 4, 2021​ View Full Advisory » The avalanche danger is MODERATE this morning trending to CONSIDERABLE by this afternoon in the west central Montana backcountry today. New snow and wind are creating dangerous avalanche conditions. Human triggered avalanches are possible this morning and become more likely this afternoon and tomorrow. Good Morning. This is Travis Craft with the West Central Montana Avalanche Center advisory on Thursday, February 4, 2021. This advisory is sponsored by the Big Sky Brewing Company. This advisory does not apply to operating ski areas and expires at midnight tonight. The USDA Forest Service is solely responsible for its content. Weather and Snowpack Mountain temperatures range from 18 degrees to 25 degrees F this morning. 8 to 10 inches of new snow fell in the last 48 hours. Winds are 12 mph, gusting to 22 mph out of the SSW. Today and tonight, look for winds 15 mph gusting into the 30’s out of the West. 4-8 inches of snow are forecasted today and tonight with higher amounts above 7000 ft. New snow and wind are elevating the avalanche danger. In the last 48 hours, the advisory area received 6 to 12 inches of new snow. This snow fell on a variety of old snow surfaces. In the southern and central Bitterroot, it fell on surface hoar. Use hand pits and small test slopes to see how the new snow is bonding to old snow surfaces. Winds are loading leeward aspects and creating sensitive wind slabs. These were observed yesterday in the central Bitterroot and Rattlesnake. Cornices are growing in size and should be given a wide berth. Avoid glide cracks. The new snow is testing our buried weak layers. There is a lot of spatial variability from drainage to drainage and slope to slope. Yesterday near the Brushy Fork at 7000 ft to 7500 ft, I found snow depths from 3 ft to 5 and half feet deep depending on the aspect. The structures were all different. The shallowest snowpack had basal facets and propagated in my ECT near the ground. The deepest snowpack did not have this weak structure. These different depths show the variability in one drainage around an elevation band. We found weak, shallow snow in the Rattlesnake that propagated in ECT’s. Around Gash point, a facet crust combination propagated in tests at 7000 ft, and widespread collapsing was happening. The buried weak layers are becoming reactive with this new load of snow. Today make it simple, avoid wind loaded slopes. Choose low angle slopes >30 degrees that have 4 to 5 feet of snow. Avoid slopes with shallow, weak snowpacks. Pay attention to changing weather conditions. Stay alert when changing aspect and elevation to the changes in snowpack’s depth and structure. Bottom Line Keep it simple today. Choose low angle slopes. Avoid slopes with weak sugary snow. Do multiple pits investigating the layers in your pit wall. Avoid cornices and wind loaded terrain. Choose simple terrain that does not expose you to terrain traps. Avoid likely trigger points on slopes. Travel one at a time in avalanche terrain, carry a beacon, shovel, and probe. Remember to reassess conditions throughout the day and stay alert for signs of instability. Dig a pit. Look for red flags. Upcoming Education Events: Please visit our education page for an up to date list of regional educational events and course offerings. Below are a few select events and opportunities to check out. February 10th, 6-7:30 PM MST | FREE Online 1.5-hr Avalanche Awareness Session | Missoulaavalanche.org event | Delivered by A3 Pro instructors | Get more details and register HERE Public Observations Thank you to everyone who has taken the time to send in a public observation. Please keep sharing what you find and see while out in the backcountry. This online forum is a great resource to glean information about current conditions. You can now text us your observations to (406) 219-5566 when you don’t have time to fill out the observations page. Texted observations won’t get posted on the website, but will be used in the development of the forecast. Ski and ride safe. The post Avalanche Advisory for February 4, 2021 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Feb 05, 2021 07:32 pm Is this email not displaying correctly? View it in your browser.

Avalanche Warning for February 5, 2021​ View Full Advisory » An avalanche warning has been issued for the southern Mission, southern Swan, Rattlesnake, and southern and central Bitterroot mountains. The avalanche danger for the west central Montana backcountry is HIGH. The avalanche hazard is increasing with continued snowfall, rising temperatures, and wind. Human triggered avalanches are certain. Avalanches may run long distances. Travel in avalanche terrain is not recommended. This avalanche warning is valid for 24 hours. The avalanche warning will either be extended or terminated at 7:00 pm on February 06, 2021. Weather and Snowpack Strong winds and new snow are creating dangerous avalanche conditions. Today in the southern Missions, we found 20 new inches of snow and saw active transport of snow to leeward aspects. New snow is testing the weak layers in the snowpack. We were able to remotely trigger slides at Gash Point in the central Bitterroot on multiple aspects on buried weak layers. We had shooting cracks and propagations at Lolo Pass. These are all signs to stay away avalanche terrain. Avoid traveling in avalanche terrain today. Avoid being under run out zones. Expect the avalanche danger to continue to be elevated as more snow and wind continue till Monday. The Bottom Line Travel in avalanche terrain is not recommended. Avoid runout zones. You can trigger an avalanche remotely from the side, below or above you. This warning will be terminated or extended tomorrow at 7:00 pm. Ski and ride safe. The post Avalanche Warning for February 5, 2021 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Feb 06, 2021 05:14 pm Is this email not displaying correctly? View it in your browser.

Avalanche Warning for February 6, 2021​ View Full Advisory » The avalanche warning has been extended for the southern Mission, southern Swan, Rattlesnake, and southern and central Bitterroot mountains. The avalanche danger for the west central Montana backcountry is HIGH. The avalanche hazard is increasing with continued snowfall, rising temperatures, and wind. Human triggered avalanches are certain. Avalanches may run long distances. Travel in avalanche terrain is not recommended. This avalanche warning is valid till Monday, February 08, 2021 . The avalanche warning will either be extended or terminated at 7:00 am on February 08, 2021. Weather and Snowpack Strong winds and new snow are creating dangerous avalanche conditions. Today in the southern Missions, picked up another 12 inches of snow and saw active transport of snow to leeward aspects. New snow is testing the weak layers in the snowpack. We were able to remotely trigger slides yesterday at Gash Point in the central Bitterroot on multiple aspects on buried weak layers. We had shooting cracks and propagations at Lolo Pass. These are all signs to stay away from avalanche terrain. Yesterday in the Rattlesnake we were getting shooting cracks and remote triggering slides on 30 degree slopes. Natural slides were reported by the warming hut on north facing slopes in the Seeley Lake area. Avoid traveling in avalanche terrain today. Avoid being under run out zones. Expect the avalanche danger to continue to be elevated as more snow and wind continue till Monday. Beware of slopes above you. The Bottom Line Travel in avalanche terrain is not recommended. Avoid runout zones. You can trigger an avalanche remotely from the side, below or above you. Natural avalanches are likely. This warning will be terminated or extended tomorrow at 7:00 pm. Ski and ride safe. The post Avalanche Warning for February 6, 2021 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory Posted: Feb 08, 2021 06:59 am Is this email not displaying correctly? View it in your browser.

Avalanche Advisory for February 8, 2021​ View Full Advisory » The Avalanche Warning is terminated this morning. The avalanche danger in the west central Montana backcountry is HIGH on leeward slopes and CONSIDERABLE on all other slopes. Dangerous avalanche conditions exist and travel in avalanche terrain is not recommended. Good Morning. This is Jeff Carty with the West Central Montana Avalanche Center advisory on Monday, February 8th, 2021. This advisory does not apply to operating ski areas and expires at midnight tonight. The USDA Forest Service is solely responsible for its content. Weather and snowpack In the past week, the forecast area has received a massive amount of snow. 4.3” of SWE fell on the southern Missions, 3.1” in the Rattlesnake, 4.4″ in the central Bitterroot, and 2.8″ in the southern Bitterroot. This is a huge stress on the snow pack, translating to up to 4 feet of new snow, and it is still adjusting to the load. Of particular concern are faceted areas that were showing signs of weakness before the storm. Forecast area wide, mid elevations had well developed facets and depth hoar, as did the Rattlesnake at all elevations. These instabilities are now up to 6′ below the new snow and could produce very large destructive avalanches. In addition, near surface facets and facet/crust combo from January 13 underlie much of the new snow. These were collapsing and producing avalanches over the weekend under only part of the load we now have. More snow is expected today. Winds have increased to moderate and are transporting ample new snow to leeward slopes and creating dangerous windslab that could be well over 6 feet thick in spots. Prior to the storm, cornices were already large and collapsing. Any that remain are unstable, unpredictable, and could trigger larger avalanches if they fall. In the past 7 days, there have been 15 avalanche fatalities in the US, including one in the northern Swans on Saturday. This is the most avalanche deaths in a week since 1910. The snowpack throughout the western US is unstable and precarious. Don’t add to the numbers. Now is not the time to push into steep terrain. The snowpack needs time to settle out and bond. The Bottom Line Travel in avalanche terrain is not recommended, dangerous avalanche conditions exist. Avoid slopes over 30º and runout zones. You can trigger an avalanche remotely from the side, below, or above you. Natural avalanches are likely, human triggered avalanches in wind slab are certain. Ski and ride safe. The post Avalanche Advisory for February 8, 2021 appeared first on Missoula Avalanche.