2018-19 "Post-Season Report" 4/23/19 West Central Montana avy conditions.

[Scott]

Current West Central Montana Avalanche Advisory
Posted: Jan 01, 2019 06:23 am
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Missoula Avalanche
Avalanche Advisory for January 1, 2019

considerable danger
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The current avalanche danger is CONSIDERABLE in the west central Montana backcountry on all slopes. Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route-finding, and conservative decision-making are essential. Human triggered avalanches are likely today.

Good morning, this is Travis Craft with the West Central Montana Avalanche Center’s avalanche advisory for January 01, 2019. This danger rating 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 -7 F to 8 F. In the Bitterroot winds are 3 mph with gusts of 7 mph out of the SW. In the northern part of the advisory area, winds are calm(here is link for wind data). The region received a trace to 1 inch of new snow in the last 24 hours.

The forecast area has a weak snowpack. The weak layers in our snowpack are easily triggered by humans. Do not travel below or above runout zones. These layers have proven they are responsive to remote triggers(Public Observations). The recipe for an avalanche is present throughout our region. Give yourself a wide margin for error.

The primary avalanche problem is persistent slabs. The snowpack is giving red flags. We are still getting localized and widespread collapsing when touring. These red flags are sure signs of snowpack instabilities. This means there are dangerous avalanche conditions present. The weak layers are propagating in our snow pit tests.

The second avalanche concern is wind slabs. The last storm had strong winds with plenty of snow available for transport to leeward slopes. We saw several natural releases 6 inches deep on several different aspects due to the shift of winds during the previous storm. Identify wind drifted terrain and avoid it. The slabs on wind drifted terrain will be sensitive to human triggers.

The bottom line is dangerous avalanche conditions exist throughout our forecast area. Recreate on terrain less than 30 degrees and give yourself a large margin for error. This is not the time to push into steep terrain. I dug several pits yesterday. I had one pit that did not have unstable results. As I was coming over the ridge to dig, I got collapsing and shooting cracks. A stable result in my pit plays a very small role in my decision-making process, and the red flag data coming over the ridge tells me we have unstable conditions no matter what my pit tells me(video).

Avalanche and Weather Outlook

The next chance for precipitation is the end of the weekend. See the forecast here. Look for the snowpack to still be sensitive to human triggers with the predicted weather.

If you get out into the mountains, please share what you see on our public observations page. They are not only helpful to your community but extremely helpful to us.

Ski and ride safe.



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[Scott]

Current West Central Montana Avalanche Advisory
Posted: Jan 03, 2019 06:30 am
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Missoula Avalanche
Avalanche Advisory for January 3, 2019

moderate danger
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The avalanche danger for the west central Montana backcountry is MODERATE. Large avalanches can be triggered in isolated locations, and smaller avalanches are possible in specific terrain. Careful evaluation is needed to identify features of concern.

Good morning, this is Travis Craft with the West Central Montana Avalanche Center’s avalanche advisory for January 03, 2019. This danger rating 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 12 F to 27 F. In the Bitterroot winds are 9 mph with gusts of 12 mph out of the SW. In the northern part of the advisory area, winds are 6 mph and gusting to 12 mph out of the South(here is link for wind data). The region received 2 to 3 inches of new snow in the last 24 hours.

The primary avalanche problem is wind slabs. These slabs are located on leeward slopes, and any wind drifted piece of terrain. These slabs will be sensitive to human triggers and may have the potential to step down to weaker layers in the snowpack.

The second avalanche problem is persistent slabs. Dig a pit and pay attention to red flag data while traveling. The buried surface hoar and depth hoar are becoming less reactive in deeper snowpacks but are still able to be triggered in shallow snowpacks.

Bottom line the weak layers in our snowpack are gaining strength. But these weak layers are guilty until proven otherwise. Look for snowdrifts and smooth, rounded deposits of snow on ridgelines. There are small wind slabs on leeward terrain. Avoid likely trigger spots near rock outcrops and convexities on slope transitions.

Avalanche and Weather Outlook

Look for temperatures to moderate in the next couple of days and high winds. See the forecast here. The avalanche will rise with these conditions. Pay attention to changing weather conditions which mean that avalanche danger will change too.

Join us tonight at 6:00 pm at Big Sky Brewing for Beers with Forecasters.

If you get out into the mountains, please share what you see on our public observations page. They are not only helpful to your community but extremely helpful to us.

Ski and ride safe.





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[Scott]

Current West Central Montana Avalanche Advisory
Posted: Jan 05, 2019 06:13 am
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Missoula Avalanche
Avalanche Advisory for January 5, 2019

moderate danger
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The avalanche danger for the west central Montana backcountry is MODERATE. Large avalanches can be triggered in isolated locations, and smaller avalanches are possible in specific terrain. Careful evaluation is needed to identify features of concern.

Good morning, this is Travis Craft with the West Central Montana Avalanche Center’s avalanche advisory for January 05, 2019. This danger rating 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 F to 28 F. In the Bitterroot winds are 14 mph with gusts of 19 mph out of the SW. In the northern part of the advisory area, winds are 5 mph and gusting to 8 mph out of the ESE(here is link for wind data). The region received 1 to 3 inches of new snow in the last 24 hours.

The snowpack is slowing gaining strength. The buried surface hoar, depth hoar, and facets are less reactive in pit tests. Winds created new wind slabs on leeward terrain.

The primary problem is wind-drifted snow. Look for snowdrifts and smooth, rounded deposits of snow on ridgelines. There are small wind slabs on leeward terrain. Red flag data for wind slabs are shooting cracks when traveling across terrain. Avoid wind drifted slopes today.

The second avalanche concern is persistent slabs. The buried surface hoar and depth hoar are becoming less reactive in deeper snowpacks but are still able to be triggered in shallow snowpacks(near rock bands and cliffs). Dig a pit to the ground and see how reactive these layers are. Whumpfing and localized collapsing are sure signs of instability.

The bottom line: avoid wind loaded terrain. Do not trust our buried weak layers . Dig a pit and avoid likely trigger points on slopes where shallow snow exists(cliff bands, rock outcrops, and slope transitions). Use small test slopes with low consequences to get a feel for the snowpack.

Avalanche and Weather Outlook

Snow is in the forecast for Sunday. With the addition of a little snow look for the avalanche danger to stay the same.

Ski and ride safe.

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[Scott]

Current West Central Montana Avalanche Advisory
Posted: Jan 08, 2019 06:29 am
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Missoula Avalanche
Avalanche Advisory for January 8, 2019

considerable danger
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The back country avalanche danger is CONSIDERABLE on wind loaded terrain for West Central Montana. Human triggered avalanches are likely on wind drifted terrain. Careful route finding and snowpack evaluation are essential for backcountry travel today. On all other terrain a MODERATE avalanche danger exists with the potential for large avalanches in isolated terrain.

Good morning, this is Logan King with the West Central Montana Avalanche Center’s avalanche advisory for Tuesday, January 8th, 2019. This danger rating 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

Overnight an additional 1-4 inches of snow fell adding up to 0.3 inches of SWE. Bringing snow totals over the last couple of days up to 10-18 inches across the forecast area. Winds were strong and gusting into the 40 mph range yesterday but have calmed this morning and are from the SE-SW at 5-10 mph with gusts into the 20’s. Mountain temperatures this morning range from 5-17 degrees as of 5 am.

The storm that began to impact the region this weekend has drawn to a close. The storm came in “right side up” starting warm and getting colder resulting in cold dry snow on top of warmer dense snow. This is the good news, however there is lots of new surface snow that is readily transported by the wind and the bad news is that the combination of strong winds and plenty of snow for transport has resulted in the formation of touchy wind slabs.

Wind-drifted snow is the primary concern today. Wind slabs are growing and loosing strength and are further complicated by the variability of the wind over the last three days. Yesterday we were able to find wind loading on nearly all aspects and also observed moderate to strong winds from nearly every direction on the compass over a short period of time. This means that wind slabs can be found on any aspect but will likely be confined to upper elevations and near ridges. What terrain is wind loaded is not easily identified so be diligent with observations while traveling and keep an eye out for cross loaded terrain.

Persistent slabs are an ongoing concern as well. Persistent slabs are generally gaining strength and are not overly burdened by the new snow but continue to be reactive in isolated areas. Facets, buried surface hoar, and depth hoar can be found through the forecast area. The weak persistent layers are reactive and propagating in stability tests in isolated locations. As the likelihood of triggering these weak layer slowly drops the consequences of them failing is increasing drastically. Before committing to avalanche terrain dig a pit to identify if a weak persistent layer is present. Avoid locations with shallow or rocky terrain where the weak layers will be closer to the surface and more easily triggered.

There was an avalanche fatality over the weekend near Choteau, MT, an incident investigation was performed by the Flathead Avalanche Center and the results can be found here, this occurred outside of any forecast area. There was also an avalanche accident on the 5th in the Swan range, within the forecast area of the Flathead Avalanche Center that resulted in serious injuries. An incident investigation was performed yesterday with more info to come but the preliminary information can be obtained here. We share this information to help you make better informed decisions and learn, we ask that questioning and judging others is foregone in order to move forward from these sad events.

Avalanche and Weather Outlook

Calm winds and increasing cloud cover today will allow the snow to settle and gain strength. The avalanche danger will slowly decrease before the next system starts to impact the region on Wednesday.

Ski and ride safe.

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[Scott]

Current West Central Montana Avalanche Advisory
Posted: Jan 10, 2019 05:26 am
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Missoula Avalanche
Avalanche Advisory for January 10, 2019

moderate danger
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The avalanche danger for the West Central Montana backcountry is MODERATE. Heightened avalanche conditions exist on specific terrain features and human triggered avalanches are possible. Carefully evaluate snow conditions to identify areas of heightened concern before committing to avalanche terrain.

Good morning, this is Logan King with the West Central Montana Avalanche Center’s avalanche advisory for Thursday, January 10th, 2019. This danger rating 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 as of 4 am this morning are just above freezing and did not get below 32 overnight at the majority of locations in the forecast area. Winds are light and out of the SW-SE. A few locations picked up 1-2 inches of snow overnight and saw light rain at lower elevations but the majority of the region remained dry overnight.

Conditions continue to settle and the snowpack is slowly gaining strength. The primary concern today is persistent slab avalanches. Yesterday we found isolated areas that had buried surface hoar that was breaking down and rounding but propagated readily in stability tests. The BSH appears to only be reactive in isolated areas as we received reports over the last few days of mixed results of where theses layers are reactive. Because this layer is breaking down it can be hard to identify but is easily seen when performing stability tests (video). Furthermore, areas of shallow snow can still be found throughout the region and will be another persistent problem. With facets at the bottom of our snowpack shallow snow, rocky terrain and steep rollovers will all be likely trigger points for persistent weak layers near the ground.

Wind slabs are the second avalanche concern today. They are primarily at upper elevations above about 6,000 ft but can be found in some unusual places with the predominant southern flow we’ve been seeing this winter. Winds have calmed and slab growth has diminished but there are still some wind slabs near ridges and hiding in pockets that are primed and waiting for a trigger. Carefully evaluate wind loaded terrain before traveling on or below any slope.

The curve ball today is wet avalanches. With mountain temperatures forecasted to reach the 40’s today the potential for wet avalanches may develop. Keep in mind that the snowpack doesn’t like rapid changes and a quick warm up with lots of sun is a perfect example of a rapid change that can increase avalanche activity. If you start to observe pinwheels and rollerballs change aspects or elevations to find a cooler zone as they are the first indicators of wet avalanche potential.

Conditions right now are very complex and highly variable. Don’t be fooled by the moderate danger rating into thinking things are safe or straight forward. I’ll say it again, heightened avalanche conditions exist on specific terrain. Remember that the danger rating is based on distribution, likelihood, and size of potential avalanches and with our current conditions there are places where you can/will trigger avalanches if you are in the wrong place at the wrong time. Carefully evaluate the snowpack before venturing into avalanche terrain.

Avalanche and Weather Outlook

Scattered showers are possible today with minimal accumulations. The forecast is calling for temperatures approaching 40 degrees but cloudy. The avalanche danger will increase slightly through the day today due to warming and will likely climb further tomorrow with warm temperatures and mostly sunny skies. Some of the scattered snow showers will have the potential to rain to just below 5,000ft. Rain on snow will create more instability at lower elevations.

Tonight Big Sky Brewing is hosting another beers with forecasters from 6-8pm. Feel free to stop by and ask Travis and I some questions, give us some feed back or just talk shop. There is also a fully function beacon park to practice your rescue skills. We hope to see you there. As always, if you make it out please feel free to share what you find on our public observations page.

Ski and ride safe.

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[Scott]

Current West Central Montana Avalanche Advisory
Posted: Jan 12, 2019 05:56 am
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Missoula Avalanche
Avalanche Advisory for January 12, 2019

moderate danger
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The current avalanche danger is MODERATE for the West Central Montana backcountry. Heightened avalanche conditions exist on specific terrain where avalanches can easily be triggered. Carefully evaluate how likely the snow is to slide and how severe the consequences will be before venturing into avalanche terrain.

Good morning, this is Logan King with the West Central Montana Avalanche Center’s avalanche advisory for Saturday, January 12th, 2019. This danger rating 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

Winds are calm this morning and no new snow fell overnight. As expected with the inversion lower elevation snotels have temperatures in the low teens and upper elevation snotel temperatures are in the low twenties.

The primary concern today continues to be persistent slab avalanches. On cool shaded aspects with shallow snowpacks facets and surface hoar continue to propagate in stability tests. Yesterday Travis found weak facets near the ground that were propagating in the Rattlesnake (video) and I found buried surface hoar and facets, both of which were propagating in the Central Bitterroot (video). The common denominator was that all of the propagations were occurring in colder shaded areas with shallow snow depths. The concern is that you don’t know if the persistent weak layers are present and reactive until you dig a pit and perform stability tests. Alarmingly, if the persistent layers fail they will create a large avalanche with very high consequences. Now is not the time to roll the dice, make conservative decisions because the avalanches that we are dealing with would be very dangerous.

Stay aware as conditions change throughout the day. The potential for wet avalanches will develop through the day with warm temperatures and plenty of sunshine in the mountains. If you see rollerballs and pinwheels start to roll down slopes and the snow starts to get wet and heavy move to a cooler aspect.

Avalanche and Weather Outlook

An inversion will dominate the region this weekend. Expect to see valley fog and warm daytime temperatures in the mountains with cold clear nights leading to continued surface hoar growth. Avalanche conditions will remain the same through the weekend (forecast).

The Snowbowl beacon park was put in yesterday and is up and running. If you are up there stop in and get some practice with your gear. If you get out this weekend, please feel free to share what you find on our public observations page.

Ski and ride safe.

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[Scott]

Current West Central Montana Avalanche Advisory
Posted: Jan 15, 2019 06:16 am
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Missoula Avalanche
Avalanche Advisory for January 15, 2019

moderate danger
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The avalanche danger for the west central Montana backcountry is MODERATE. Large avalanches can be triggered in isolated locations, and smaller avalanches are possible in specific terrain. Careful evaluation is needed to identify features of concern.

Good morning, this is Travis Craft with the West Central Montana Avalanche Center’s avalanche advisory for January 15, 2019. This danger rating 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 10 F to 29 F. In the Bitterroot winds are 13 mph with gusts of 19 mph out of the SE. In the northern part of the advisory area, winds are 6 mph and gusting to 10 mph out of the NW. There was no new snow.

The snowpack is gaining strength on certain aspects and slopes. We are still finding facets that are reactive in pit tests. We are still getting reports of human-triggered slides. The facets are most reactive in shallow snowpacks. We are also getting reports of propagations in pit tests on buried surface hoar(Public Observations, Video).

The primary avalanche problem is persistent slabs. There are facets at the bottom of our snowpack throughout the advisory area. There is buried surface hoar 50 to 70 cm from the snow surface on some aspects and slopes. These two layers are slowly gaining strength but are still reactive on certain slopes. The primary way to mitigate these problems is to avoid likely trigger points on slopes where the snowpack is shallower. The second is to dig a pit and see how reactive these layers are. There is a lot of variability in snowpack depths; some bullseye data is if you get off of your skis or machine and sink to the ground you have found our shallow, weak snowpack. It is getting harder to trigger avalanches but take the time to assess each slope and aspect.

Bottom line: Use safe travel protocols, travel one person at a time in avalanche terrain, dig a pit, and avoid likely trigger points on slopes where shallow snow exists(cliff bands, rock outcrops, and slope transitions).

Avalanche and Weather Outlook

Cooler weather is coming to the mountains as the inversion breaks. Snow and wind are predicted for tonight. Over the last dry spell surface hoar has been forming. With new snow look for the surface hoar to be our new problem when it is buried(video). See the forecast. Fresh snow and buried surface hoar will increase the avalanche danger on slopes.

If you get out into the mountains, please share what you see on our public observations page. They are not only helpful to your community but extremely helpful to us.

Ski and ride safe.







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[Scott]

Current West Central Montana Avalanche Advisory
Posted: Jan 17, 2019 06:44 am
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Missoula Avalanche
Avalanche Advisory for January 17, 2019

moderate danger
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The avalanche danger for the west central Montana backcountry is MODERATE on slopes with a shallow snowpack. All other slopes are LOW. Large avalanches can be triggered in isolated locations, and smaller avalanches are possible in specific terrain. Careful evaluation is needed to identify features of concern. The danger will rise throughout the day and may reach CONSIDERABLE by Friday morning.

Good morning, this is Travis Craft with the West Central Montana Avalanche Center’s avalanche advisory for January 17, 2019. This danger rating 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 23 F to 28 F. In the Bitterroot winds are 15 mph with gusts of 23 mph out of the ESE. In the northern part of the advisory area, winds are 9 mph and gusting to 13 mph out of the ESE. It has just started to snow this morning.

The snowpack is relatively stable this morning. There are a variety of old snow surfaces (melt-freeze crusts, surface hoar, and near surface facets) for the new snow to land on. The fresh snow will take time to bond to the old snow. The addition of snow will make our buried weak layers(facets and buried surface hoar) more sensitive to natural triggers(new weight from snow) and human triggers. With the weather change the avalanche conditions will change.

The primary avalanche problem today is persistent slabs. The buried weak layers in our snowpack are getting harder to trigger. These layers are more reactive in shallow, weak snowpacks less than 3 feet deep(video).

The other two problems will be wind drifted snow and new snow. The new snow will land on a variety of old snow surfaces and winds will load leeward slopes on the old snow surfaces too. These slabs will be sensitive to human triggers today and Friday.

Bottom line: The snowpack is fairly stable this morning. The new snow will create new problems throughout the day into Friday. Pay attention to the changing weather and changing avalanche conditions. Constantly reevaluate your route and carefully assess each slope when recreating today.

Avalanche and Weather Outlook

It is starting to snow this morning and is predicted to continue through Friday. See the forecast here. The new snow will be landing on a variety of old snow surfaces and buried weak layers. This recipe will increase the avalanche danger.

If you get out into the mountains, please share what you see on our public observations page. They are not only helpful to your community but extremely helpful to us.

Ski and ride safe.

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[Scott]

Current West Central Montana Avalanche Advisory
Posted: Jan 18, 2019 06:49 am
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Missoula Avalanche
Avalanche Advisory for January 18, 2019

high danger
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The current avalanche danger for the west central Montana backcountry is HIGH on wind loaded slopes and CONSIDERABLE on all other slopes. Avoid traveling on or below wind loaded slopes. Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route-finding, and conservative-decision making are essential to recreate today.

Good morning, this is Travis Craft with the West Central Montana Avalanche Center’s avalanche advisory for January 18, 2019. This danger rating 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 23 F to 32 F. In the Bitterroot winds are 7 mph with gusts of 20 mph out of the West. In the northern part of the advisory area, winds are 3 mph and gusting to 6 mph out of the ESE. The forecast area has received 6 to 12 inches of snow adding between .6 and 1.3 SWE to the snowpack.

The primary avalanche problem today is wind drifted snow. Wind slabs are on leeward slopes (video).These slabs have been deposited on a variety of old snow surfaces and will be very sensitive to human triggers. Identify wind drifted terrain; look for rounded pillows and shooting cracks. Avoid traveling on or under wind drifted terrain today.

The second avalanche concern is storm slabs. New snow has been deposited on a variety of old snow surfaces(near surface facets, surface hoar, and a variety of crusts) and needs time to bond. These slabs will be reactive to human triggers today.

The last problem is persistent slabs. The new snow will add additional weight to our weak layers in the snowpack and may reactivate some of the layers that have been dormant(facets at the base of our snowpack and buried surface hoar).

Bottom line: We have dangerous avalanche conditions in our forecast area. Avoid wind drifted terrain. Choose low angle slopes(less than 30 degrees) to enjoy the new snow. It is a real possibility to trigger a wind slab or storm slab on steep terrain and have it step down into the bottom of our snowpack and cause a large or very large avalanche.

Avalanche and Weather Outlook

The region will continue to have scattered showers till the afternoon. Then a new system will move in on Saturday. See the forecast here. I will issue the next advisory tomorrow.

If you get out into the mountains, please share what you see on our public observations page. They are not only helpful to your community but extremely helpful to us.

Ski and ride safe.



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[Scott]

Current West Central Montana Avalanche Advisory
Posted: Jan 19, 2019 06:32 am
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Missoula Avalanche
Avalanche Advisory for January 19, 2019

considerable danger
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The current avalanche danger for the west central Montana backcountry is CONSIDERABLE. Dangerous avalanche conditions are present. Careful snowpack evaluation, cautious route-finding, and conservative-decision making are essential to recreate today.

Good morning, this is Travis Craft with the West Central Montana Avalanche Center’s avalanche advisory for January 19, 2019. This danger rating 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 23 F to 27 F. In the Bitterroot winds are 14 mph with gusts of 27 mph out of the SSE. In the northern part of the advisory area, winds are 15 mph and gusting to 19 mph out of the East. 2 inches of new snow overnight, and it is currently snowing in the mountains.

Yesterday we saw natural avalanches of storm slabs on slick crusts. Logan and I found the storm slabs to be settling out throughout the day and bonding to the old snow surfaces. Moderate to strong winds were cross loading some slopes, ridgetops, and creating large cornices.

The primary avalanche problem is wind drifted snow. Moderate to strong winds have deposited wind slabs on leeward terrain. Look for smooth rounded pillows and drifts on ridges and cross-loaded slopes. Identify these slopes and avoid traveling on them. These slabs will be sensitive to human triggers today.

The second avalanche problem is persistent slabs. Yesterday’s snow fell on slick crusts and in mid elevations(5000ft to 6500ft) surface hoar. These layers released naturally yesterday but on slopes that did not release, are primed for human triggering. The deeper layers(facets on the ground and earlier buried surface hoar) were not reactive in tests yesterday; these layers are guilty until proven otherwise. Dig a pit to see how the new snow has bonded to the old snow surface and if buried surface hoar is present on the slope, dig down to the ground to see if the facets and buried surface hoar are reactive to the new load of snow. These layers can surprise us by becoming active again after weeks of being dormant.

Bottom line: The snowpack is adjusting to the new load of snow. Avoid wind drifted slopes. Dig a pit and see how the fresh snow is bonding and if the persistent weak layers are reactive in pit tests. Pay attention to changing weather conditions and avalanche conditions. Look for shooting cracks, natural activity, and collapses; these are clues to instabilities in the snowpack. Choose lower angle terrain(less than 30 degrees).

Avalanche and Weather Outlook

Snow is forecasted for today and into Sunday. See the forecast here. The mountains are predicted to get 3-7 new inches of snow. Expect the avalanche danger to rise.

If you get out into the mountains, please share what you see on our public observations page. They are not only helpful to your community but extremely helpful to us.

Ski and ride safe.

The post Avalanche Advisory for January 19, 2019 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory
Posted: Jan 21, 2019 06:39 am
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Missoula Avalanche
Avalanche Advisory for January 21, 2019

considerable danger
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Currently, a CONSIDERABLE avalanche danger exists for the West Central Montana backcountry. Dangerous avalanche conditions are present and human triggered avalanches are likely on specific terrain and at certain locations. Careful snowpack evaluation, cautious route-finding, and conservative-decision making are essential for mountain travel today.

Good morning, this is Logan King with the West Central Montana Avalanche Center’s avalanche advisory for Monday, January 21st, 2019. This danger rating 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

Sunday brought another round of snow to West Central Montana. Snowfall started mid-morning yesterday and has since deposited 4-8 inches of new snow and up to 0.5 inches of SWE. The storm came in with light southerly winds which have shifted to a more westerly flow and are currently 5 mph with gust to around 8 mph.

The biggest concern today continues to be persistent slabs. A significant load of new snow has fallen across the region and at many locations is sitting on a variety of weak layers and bed surfaces. There is a pronounced layer of large surface hoar that formed over the dry spell from the last few weeks. This is primarily found in a band at mid to low elevations around 5,000 feet to 6,500 feet. We were worried about this layer as snow returned to the region, and our concerns were confirmed over the weekend as we received numerous reports (public observations) of significant instability in locations where the surface hoar has been buried including; whumphing, shooting cracks and a human triggered slide.

There are also locations where surface hoar has been buried but is much smaller and not as reactive. This layer is more widespread and harder to pinpoint until you start to perform stability tests. Similarly there are some aspects that formed a melt freeze or sun crust instead of forming facets and surface hoar. Locations that have a stout crust will take longer to bond with the new snow and will also provide a good bed surface for the newly formed slab to slide on.

The weak faceted snow near the ground and the older BSH layers should be on your radar again as they are not likely to be triggered by a skier or rider but will easily step down if a slide is initiated on a slope. Keep in mind that if you are able to trigger these layers directly or indirectly that the resulting avalanche will be very large and will have high consequences.

Finally the new snow will need another day or two to settle and bond regardless of what surface it has been falling on. Winds were relatively light with this storm system but locations with any wind deposited snow will have an increased avalanche danger. Remember that the majority of avalanche accidents occur within a day or two following a storm. Avoid steep terrain for a few more days at least to allow the new snow some time to gain strength.

Avalanche and Weather Outlook

Snow is expected to continue through mid-day today before dropping of later today. The Avalanche danger will remain the same through the day today and will slowly start to decrease over the next few days.

If you get out into the mountains, please share what you see on our public observations page. They are not only helpful to your community but extremely helpful to us.

Ski and ride safe.

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[Scott]

Current West Central Montana Avalanche Advisory
Posted: Jan 22, 2019 06:15 am
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Missoula Avalanche
Avalanche Advisory for January 22, 2019

considerable danger
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The avalanche danger is CONSIDERABLE between 5,000 and 6,500 feet for the West Central Montana backcountry. Human triggered avalanches are likely in this elevation band. Carefully evaluate the snowpack and terrain, and utilize conservative routes and decision making in order to avoid avalanches today. On terrain above 6,500ft the avalanche danger is MODERATE.

Good morning, this is Logan King with the West Central Montana Avalanche Center’s avalanche advisory for Tuesday, January 22nd, 2019. This danger rating 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

Skies cleared overnight and mountain temperatures dropped. As of 5 am this morning, temperatures are in the teens across the region. Winds are calm out of the SW at 7 mph with gusts up to 10 mph. Most mountain locations did not see any snow since yesterday afternoon, but a few isolated locations picked up an additional 1-2″ of snow.

During the extended inversion earlier this month, large surface hoar formed between approximately 5,000ft-6,500ft. This surface hoar is now buried under 12-24 inches of snow and is easily triggered. Locations where the BSH is present have been showing many signs of instability such as whumphing, shooting cracks and even resulted in a human triggered slide over the weekend. If you are recreating below 6,500 feet, make sure that this layer is not present before traveling on, below, or near avalanche terrain. Persistent weak layers like BSH have the ability to propagate failures long distances, so give any slope with BSH a wide berth.

The older layers of BSH continue to gain strength but can’t be fully trusted yet. Facets can be found at the bottom of the snowpack throughout the forecast area as well. These persistent weak layers will be a concern at all elevations but are not nearly as reactive in stability tests. Take a few minutes to dig a pit to see if these layers are present and reactive before committing to avalanche terrain. Avoid areas with shallow snow or near rock outcrops, as they are likely trigger points for these layers.

Wind slabs can be found at upper elevations near ridges and in isolated pockets. Winds have been variable so small pockets of wind loaded terrain can be found on nearly any aspect. With the shifting winds, cross loaded terrain will be difficult to identify so keep your eyes peeled for any signs of recent wind transport.

Avalanche and Weather Outlook

Today should bring a relatively calm weather pattern before another systems moves in tonight (forecast). The avalanche danger will not change much today but will climb Wednesday as the snow starts to pile up. Snow should start to accumulate tonight with another 6+ inches possible through the day tomorrow (forecast) but rain lines are still in question through the afternoon tomorrow. Snow totals by Thursday morning will be close to a foot at most locations if the system plays out as expected.

If you get out into the mountains, please share what you see on our public observations page. They are not only helpful to your community but extremely helpful to us.

Ski and ride safe.

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[Scott]

Current West Central Montana Avalanche Advisory
Posted: Jan 24, 2019 06:46 am
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Missoula Avalanche
Avalanche Advisory for January 24, 2019

considerable danger
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A CONSIDERABLE avalanche danger exists across the West Central Montana backcountry. Cautious route finding, conservative decision making, and careful snowpack and terrain evaluation are essential. Human triggered avalanches are likely throughout the forecast region.

Good morning, this is Logan King with the West Central Montana Avalanche Center’s avalanche advisory for Thursday, January 24th, 2019. This danger rating 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 this morning are in the low 20’s. Winds are out of the W in the Southern Bitterroot at 3 mph gusting to 6 mph. In the Northern half of the advisory area winds are out of the WSW at 7 mph gusting to 12 mph. Little to no new snow fell over night. Yesterday’s snow totaled between 8-14 inches across the region and added a load of 0.6-1.0 inches of SWE.

There are three different problems that you will have to deal with in the backcountry today. Any of these problems can be found at a given location and it is up to you to determine which is the greatest concern for a specific slope.

The obvious first problem is storm slabs. Soft storm slabs started to develop later in the day yesterday as temperatures began to warm. The changing temperatures resulted in an upside-down slab with heavy warm snow overlying cold dry snow. The interface in the new snow was increasingly reactive through the day yesterday and was even yielding shallow failures in tests with easy propagation (profile). The storm slabs are widespread and can be found at most locations, carefully assess the snow to identify if there is a soft storm slab that will be reactive. The storm slabs will need another day or two to settle and bond before this problem subsides.

The second avalanche problem to be aware of today are wind slabs. Winds started out of the S and shifted to the NW and created wind slabs on lee terrain. The wind slabs are more touchy than the storm slabs and will create slightly larger avalanches as well. Look for signs of wind loading to identify areas of increased risk. Wind slabs will be primarily located near ridges but will also be found in isolated pockets across terrain.

The next problem, and most challenging to deal with is persistent slabs. There are 3 different layers that you will need to look out for; first is buried surface hoar. There are multiple layers of BSH, one of which is the newest which is large and obvious at many locations and will be reactive if the slab above is stiff enough, also the older BSH has become reactive again under the new load and was resulting in deeper failures yesterday (Video 1). The deeper BSH will result in large avalanches with high consequences, as will the second persistent layer which is depth hoar/basal facets. That’s right, the new load has re-activated the weak snow near the ground at some locations (Video 2). Finally there is a melt freeze crust that formed at the same time as the surface hoar which is providing a slick bed surface for the newer snow to slide on.

The bottom line is that there are multiple problems that are requiring complex analysis and are making decisions challenging to make. Slow down, take your time to perform stability tests, talk with your partners and come back another day if you are unsure. Not only is the likelihood of triggering an avalanches high but the consequences of some of them would be severe. Err on the side of caution if you are in the backcountry today.

Avalanche and Weather Outlook

Other than the potential for an uptick in wind speeds today the weather looks to be benign (forecast). Avalanche danger will mostly remain the same today until the next loading event which looks to be setting up for Friday.

We hope to see you tonight at Big Sky Brewing from 6-8, for our final Beers with Forecasters for the season. If you are out into the mountains today, please share what you see on our public observations page. Your observations are not only a great resource to us but can be extremely helpful to our community.

Ski and ride safe.

The post Avalanche Advisory for January 24, 2019 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory
Posted: Jan 26, 2019 06:45 am
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Avalanche Advisory for January 26, 2019

considerable danger
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The current avalanche danger is CONSIDERABLE for the West Central Montana backcountry. Conditions are improving but are still touchy. Human triggered avalanches are likely on specific terrain. Utilize conservative decisions, thorough snowpack evaluation and keen terrain evaluation to safely travel in the backcountry today.

Good morning, this is Logan King with the West Central Montana Avalanche Center’s avalanche advisory for Saturday, January 26th, 2019. This danger rating 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

Winds this morning are out of the WSW at 10 mph with gusts up to 18 mph. Mountain temperatures as of 4 am range from 23-28 degreees Fahrenheit. Light and scattered showers yesterday and last night added up to 5 inches in the northern part of the advisory area while most locations only received a trace to 3 inches.

The storm slabs have settled out and the new snow is bonding to the old snow surface but the avalanche dangers is still considerable, as human triggered avalanches are likely on specific terrain and there is also potential for very large avalanches.

Persistent slabs continue to be a concern across the forecast area. There are multiple layers of buried surface hoar that continue to be reactive and propagate in stability tests. This layer is also responsible for natural releases on steep roll overs at lower elevations (pic). The facets near the ground and depth hoar continue to propagate in tests as well. These layers are not as reactive as a few days ago but are still failing at some locations and would result in large to very large avalanches. Whumphing and shooting cracks (pic) are becoming less prominent so the only way to know if these layers are present is to dig a pit and perform stability tests.

The other concern today is wind slabs. At upper elevations, near ridges and in isolated pockets wind slabs can be found that will be sensitive to human triggers. There is plenty of snow available for transport and wind slabs continue to grow in size. Look for rounded pillows of snow, cornices, and snow plastered to trees to see what locations are getting an additional load of snow and will be possible locations of avalanches. Shooting cracks have been observed on wind loaded terrain. Avoid traveling on any wind loaded terrain steeper than 30 degrees.

Conditions are improving but are not quite to the point of being trusted yet. Carefully evaluate the snowpack before committing to avalanche terrain. Keep in mind that there is a significant potential for very large avalanches, so carefully assess not just the likelihood but also the consequences of a slide.

Avalanche and Weather Outlook

Winds are expected to increase over the weekend as a cold front approaches (forecast bc). Late Sunday the winds will shift to NE and the temperature will drop as the cold front pushes in. A rapid transition is expected and the short time of frontal passage will limit the snowfall to only a few inches (snow amount) (forecast disc.). Wind slabs will continue to grow over the weekend but overall avalanche conditions will continue to slowly improve until the weather changes on Sunday.

The beacon parks at Lolo Pass, on top of Snowbowl, at Lost Trail, and at Big Sky Brewing are all up and running. Be prepared and practice your rescue skills. If you are out in the mountains today, please share what you see on our public observations page. Your observations are not only a great resource to us but can be extremely helpful to your community.

Ski and ride safe.

The post Avalanche Advisory for January 26, 2019 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory
Posted: Jan 29, 2019 06:24 am
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Avalanche Advisory for January 29, 2019

moderate danger
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The avalanche danger for the west central Montana backcountry is MODERATE. Large avalanches can be triggered in isolated locations, and smaller avalanches are possible in specific terrain. Careful evaluation is needed to identify features of concern.

Good morning, this is Travis Craft with the West Central Montana Avalanche Center’s avalanche advisory for January 29, 2019. This danger rating 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 1 F to 18 F. In the Bitterroot winds are 3 mph with gusts of 5 mph out of the SE. In the northern part of the advisory area, winds are calm. No new snow overnight.

Over the weekend we got several public observations. The main concern is still persistent slabs. Yesterday, I was able to get the facets near the ground to fail in 4 stability tests on a slope. One column propagated while I was cutting the block(Video). These are signs of instability. A skier triggered avalanche was reported over the weekend outside the advisory area in the Sapphire range(observation). There have been several fatalities in the U.S. in the last week. One was from the Tobacco Root range outside any forecast area(report). The snowpack is variable this year and is complex.

The primary concern is persistent slabs. There are buried weak layers throughout the forecast area. There is buried surface hoar 2 feet from the surface and there are facets at the bottom of the snowpack. These layers are getting harder to trigger but, if you trigger them, the avalanche will be large and have high consequences.

The only way to mitigate persistent weak layers is to dig a pit, see if these layers are present, and reactive in pit tests. The second is avoid likely trigger points on slopes(cliff bands, rock outcrops, and slope transitions) where the snowpack is shallow. Choose slopes with clean runout zones that avoid terrain traps(cliffs, trees, and rocks) and are less than 35 degrees.

The bottom line is we have a variable snowpack in the forecast area. The odds of triggering an avalanche are decreasing but if you do it will be a very large avalanche and most likely unsurvivable. Choose lower angle terrain, put your shovel in the snow and do stability tests before committing to any avalanche terrain. Keep the terrain simple, slopes that do not have lots of transitions and rocky terrain.

Avalanche and Weather Outlook

We are entering a period of high pressure. Expect the avalanche danger to stay the same. See the forecast. Look for warming on sun exposed slopes on Wednesday which will produce wet loose avalanche problems if we get the forecasted temperatures. Remember changing weather means changing avalanche danger.

The beacon checker outside the Snowbowl ski area is not working. Remember that a beacon checker does not take the place of doing a partner multifunction beacon check.

As always, if you make it out please feel free to share what you find on our public observations page.

Ski and ride safe.

The post Avalanche Advisory for January 29, 2019 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory
Posted: Jan 31, 2019 05:54 am
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Missoula Avalanche
Avalanche Advisory for January 31, 2019

moderate danger
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The avalanche danger for the west central Montana backcountry is MODERATE. Large avalanches can be triggered in isolated locations, and smaller avalanches are possible in specific terrain. Careful evaluation is needed to identify features of concern.

Good morning, this is Travis Craft with the West Central Montana Avalanche Center’s avalanche advisory for January 31, 2019. This danger rating 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 20 F to 26 F. In the Bitterroot winds are 13 mph with gusts of 18 mph out of the South. In the northern part of the advisory area, winds are calm. No new snow overnight.

Our snowpack is gaining strength. High pressure is allowing some of the weak layers to bond. Remember buried surface hoar is guilty until proven otherwise.

The primary avalanche problem is persistent slabs. There are layers of buried surface hoar in our snowpack. There are three layers, to identify them, dig a pit 3 feet deep and perform pit tests. There are facets located at the bottom of our snowpack. Dig a pit to see if they are reactive in tests and are present on the slope you want to ride. All of these layers are getting harder to trigger. If you trigger the facets on the ground, it will be a high consequence avalanche. Avoid likely trigger points on slopes(cliff bands, rock outcrops, and slope transitions) where the snowpack is shallow. Choose slopes with clean runout zones that avoid terrain traps(cliffs, trees, and rocks).

The second avalanche problem is wind drifted snow. There are small wind slabs located on mid-elevation leeward slopes. Look for snowdrifts and smooth, rounded deposits of snow. Avoid traveling on wind loaded terrain.

Bottom line: The snowpack is getting stronger. Put your shovel in the snow and check for buried weak layers. Look for signs of wind loading and avoid steep slopes with wind drifted snow.

Avalanche and Weather Outlook

High pressure will dominate until Friday. New snow will have a multitude of old snow surfaces to try to bond with, surface hoar, wind crusts, and melt-freeze crusts. Look for warming on sun-exposed slopes which will produce wet loose avalanche problems if we get the forecasted temperatures. See the forecast.

As always, if you make it out please, feel free to share, what you find on our public observations page.

Ski and ride safe.

The post Avalanche Advisory for January 31, 2019 appeared first on Missoula Avalanche.

 

[Scott]

Avalanche Advisory for February 2, 2019

moderate danger
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The avalanche danger for the west central Montana backcountry is MODERATE. Large avalanches can be triggered in isolated locations, and smaller avalanches are possible in specific terrain. Careful evaluation is needed to identify features of concern.

Good morning, this is Travis Craft with the West Central Montana Avalanche Center’s avalanche advisory for February 02, 2019. This danger rating 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 30 F to 35 F. In the Bitterroot winds are 14 mph with gusts of 24 mph out of the SSE. In the northern part of the advisory area, winds are 12 mph and gusting 16 mph out of the SSE. The winter storm is slowly entering our area with a snowline around 5500 feet. Snotels have picked up only a trace of SWE in the last 24 hours.

Today’s storm will only bring a small amount of precipitation to the region, an inch or two above 5500 feet. See the forecast here. An arctic front moves in on Sunday, look for strong winds from the east and snow lines to drop to the valley floor. Changing weather equals changing avalanche conditions.

The primary avalanche concern is small wind slabs today on leeward slopes above 6000 feet. Look for smooth rounded pillows and drifts on ridges and cross-loaded slopes. Identify these slopes and avoid traveling on them. These slabs will be sensitive to human triggers today.

The primary concern below 6000 feet is loose wet avalanche activity with warm temperatures and a rain-snow mix. Look for roller balls and avoid slopes that have pinwheels on them. If you are out on an extended tour be aware when coming out of higher elevations and heading home.

The second avalanche problem is persistent slabs. The snowpack is consolidating, but the layers of buried surface hoar and the facets near the ground are still reactive in shallow snowpacks in pit tests. All of these layers are getting harder to trigger. If you trigger the facets on the ground, it will be a high consequence avalanche. Avoid likely trigger points on slopes(cliff bands, rock outcrops, and slope transitions) where the snowpack is shallow. Choose slopes with clean runout zones that avoid terrain traps(cliffs, trees, and rocks). Dig a pit to see if these layers are present and reactive on the slope.

Bottom line: The snowpack consolidated over the last week. This storm system is predicted to drop a significant amount of snow through the weekend. New snow will be falling on a variety of old snow surfaces and will need time to bond. The weak layers in our snowpack will be tested again with additional loading. Dig a pit to assess the layers of buried surface hoar and facets near the ground. This storm will have strong winds out of the East look for wind drifted snow on leeward slopes.

Avalanche and Weather Outlook

See the forecast here. With the predicted snow totals and wind look for the avalanche danger to increase and go to CONSIDERABLE by Sunday. The new snow will be falling on a variety of old snow surfaces and will need time to bond. The strong winds will load leeward slopes. The persistent weak layers in our snowpack will be tested with new weight being added to them. Keep your head on a swivel and pay close attention to weather changes that will increase the avalanche danger.

As always, if you make it out, please, feel free to share, what you find on our public observations page.

Ski and ride safe.

The post Avalanche Advisory for February 2, 2019 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory
Posted: Feb 03, 2019 07:01 am
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Missoula Avalanche
Avalanche Advisory for February 3, 2019

considerable danger
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The avalanche danger for the west central Montana backcountry is CONSIDERABLE. Dangerous avalanche conditions are present. Look for the avalanche danger to increase throughout the day, possibly going to HIGH on wind loaded slopes by the afternoon.

Good morning, this is Travis Craft with the West Central Montana Avalanche Center’s avalanche advisory for February 03, 2019. This danger rating 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 28 F to 34 F. In the Bitterroot winds are 9 mph with gusts of 12 mph out of the SSE. In the northern part of the advisory area, winds are 7 mph and gusting 12 mph out of the ESE. Snotels are reporting between .3 and .5 SWE for the last 24 hours. The arctic front is dropping temperatures, and strong winds are increasing the avalanche danger.

The primary problem today is wind drifted snow. Look for smooth rounded pillows and drifts on ridges and cross-loaded slopes. Identify these slopes and avoid traveling on them. These slabs will be sensitive to human triggers today.

The second problem is new snow on old snow surfaces. There are a variety of old snow surfaces (melt-freeze crusts, surface hoar, and near surface facets) for the new snow to land on. The fresh snow will take time to bond to the old snow.

The last problem is persistent slabs. The new snow will add additional weight to our weak layers in the snowpack and may reactivate some of the layers that have been dormant(facets at the base of our snowpack and buried surface hoar).

Bottom line: We currently have dangerous avalanche conditions in our forecast area. More snow and wind today will increase the avalanche danger throughout the day. Avoid wind drifted terrain. Choose low angle slopes(less than 30 degrees) to enjoy the new snow. It is a real possibility to trigger a wind slab or storm slab on steep terrain and have it step down into the bottom of our snowpack and cause a large or very large avalanche.

Avalanche and Weather Outlook

Snow through Monday. Today 6 to 9 inches of new snow is predicted for the region accompanied by strong winds. These conditions will increase the avalanche danger and may push the avalanche danger to HIGH on wind loaded slopes. See the forecast here.

As always, if you make it out, please, feel free to share, what you find on our public observations page.

Ski and ride safe.

The post Avalanche Advisory for February 3, 2019 appeared first on Missoula Avalanche.

 

[Scott]

Current West Central Montana Avalanche Advisory
Posted: Feb 05, 2019 06:24 am
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Missoula Avalanche
Avalanche Advisory for February 5, 2019

moderate danger
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A MODERATE avalanche danger exists for the West Central Montana backcountry. Human triggered avalanches are possible and will produce small avalanches in specific areas with the potential for large avalanches in isolated areas. Heightened avalanche conditions exists on specific terrain and careful assessment is critical to identify areas of increased concern.

Good morning, this is Logan King with the West Central Montana Avalanche Center’s avalanche advisory for Tuesday, February 05th, 2019. This danger rating 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

As of 4am this morning a temperature inversion has developed. Mountain temperatures above about 6,500 feet are in the low twenties and at lower elevations are approximately 5-10 degrees Fahrenheit. Light snow and scattered showers yesterday have left most locations with 1-3 inches of new snow with low SWE values. Winds are light at 1-5mph and gusts up to 7 mph out of the S-SSW.

We have observed and received reports of a variety of conditions that are dependent on elevation across the forecast area, all of which will make persistent slabs the first concern today. The new snow is bonding well, but may be reactive at lower elevations where a slick rain crusts is present. At other elevations, there is surface hoar scattered across the advisory area that is creating easy propagations in stability tests, it will not be found everywhere and even when found it doesn’t always propagate. The facets near the ground are becoming less likely to trigger but can still fail in shallow areas and can’t be written of yet. The big take away with persistent slabs are that depending on your elevation, aspect, and terrain you will need to look out for a different culprit. Be vigilant with your observations and take the time to dig pits to identify what weak layers are present and how reactive they are.

The second concern today is wind drifted snow. We have seen strong Easterly winds over the last few days and there is plenty of snow for transport. The unusual direction and variability of the winds have left a lot of question marks as to where to find wind slabs and how sensitive they will be. Winds have been funneled, creating localized areas of significantly increased winds and will create wind slabs in isolated locations that are not spots you would typically see wind loading. Carefully look for indications of wind loading before committing to steep terrain and keep an eye out for cross loaded slopes.

Avalanche and Weather Outlook

Light snow showers are expected today and into tonight with minimal accumulations for the northern half of the forecast area. The southern half of the region has a greater potential of snowfall with a total accumulation of about 2-5 inches today (forecast). Winds have a chance to ramp up, but will continue to be variable across the forecast area. The avalanche danger has the potential to increase at locations receiving more snow or higher winds but should remain the same for most of the forecast area.

As always, if you make it out, please, feel free to share, what you find on our public observations page.

Ski and ride safe.

The post Avalanche Advisory for February 5, 2019 appeared first on Missoula Avalanche.

 

[Scott]

Avalanche Advisory for February 7, 2019

low danger
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The current avalanche danger for the West Central Montana backcountry is LOW. Low danger does not mean no danger! Be on the lookout for avalanches in isolated or extreme terrain.

Good morning, this is Logan King with the West Central Montana Avalanche Center’s avalanche advisory for Thursday, February 7th, 2019. This danger rating 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 this morning range from -11 to 5 degrees Fahrenheit. Winds are light out of the SW at 4 mph with gust of 6 mph. During the day yesterday the area received another 1-3 inches of new snow. Overnight mountain locations picked up a trace to an inch of new low density snow.

The most widespread problem today will be loose snow avalanches. Light and dry surface snow is moving readily throughout the advisory area. These avalanches are small and generally don’t pack much of a punch but can be dangerous if terrain traps are present. Look for cliffs, trees, gullies and anything that may increase the consequences of getting knocked off your feet or sled before committing to steep terrain.

The next problem to be aware of today are wind slabs. Lots of snow is available for transport but winds have been isolated or light. Small wind slabs are primarily confined to isolated slopes and tend to be small and soft. Winds have been erratic and blown snow back and forth over ridges so cross loading will be a problem and locations of wind slabs may be hard to identify. Carefully look for signs of wind loading before traveling in avalanche terrain.

Another problem to be on the look out for are persistent slabs. Buried surface hoar can still be found in the forecast area but is increasingly isolated and continues to gain strength. Facets near the ground are unlikely to be triggered at this point but would result in large avalanches so should be considered before venturing into big terrain. At lower elevations the new snow is bonding well with the crusts and continues to gain strength. Dig a pit to determine if these layers are present and adjust travel plans accordingly.

Big Picture: The avalanche danger continues to trend downward and is rated at low. I will say it again; Low danger does not mean no danger! It is a stout low right now and avalanches are possible if you are in the wrong place at the wrong time. Carefully evaluate the likelihood and potential consequences of avalanches before committing to avalanche terrain. Don’t treat the low rating as a green light and jump straight into big terrain, start on smaller slopes with lower consequences and test the snow before going for a big line. Stay aware of changing conditions and continue to utilize safe travel protocols and don’t but lulled into complacency.

Avalanche and Weather Outlook

Cold will dominate the region today before a small disturbance develops Friday (forecast). Another system looks to set up over the weekend that will be reminiscent of last weekends system. Cold and snow showers will continue for the next few days. The avalanche danger will remain the same unless wind loading increases or an area picks up a significant load of new snow.

As always, if you make it out, please, feel free to share, what you find on our public observations page.

Ski and ride safe.

The post Avalanche Advisory for February 7, 2019 appeared first on Missoula Avalanche.