Avy Forcast 1.20.X2
Backcountry Avalanche Forecast for Front Range
Issued: 01/20/2012 6:02 AM by Scott Toepfer
Highlights
Very strong westerly winds continue to rake the Front Range zone. In general 1 to 8" of new snow is showing up across the zone this morning. Observers are reporting some significant wind transported snow and developing wind slabs. Some below treeline locations were reporting a light rain on Thursday. This will likely develop into a crust for the next storm cycle to interact with. Probably not in a positive way.
Humans continue to trigger slab avalanches.
The first Colorado avalanche-related fatality of the season occurred on Wednesday in the backcountry near Snowmass. Our condolences go out to family and friends. A CAIC accident investigation team visited the site on Thursday. The web site has the latest known details.
Avalanche Danger
The avalanche danger for the Front Range zone is CONSIDERABLE (Level 3) on north, northeast, east, southeast, and south aspects near treeline. The danger is MODERATE (Level 2) on north, northeast, east, southeast, and south aspects above treeline, on south aspects near treeline, and on north, northeast, east, and southeast aspects below treeline. Elsewhere, the danger is LOW.
Snow & Avalanche Discussion
Strong west-southwest winds continued on Thursday across the Front Range zone. Many windward fetches are blown clean resulting in fresh loading on north through southeast aspects. The wind slabs are forming on a variety of older snow surfaces including old wind slabs, icy crusts, surface hoar, low-density storm snow, or near surface facets. Underneath all this is a very weak foundation of large facets.
An observer in the James Peak Wilderness west of Rollinsville found extremely variable conditions especially above treeline. A natural hard slab slide (2'x125'x100') occurred on a southeast aspect above treeline.
A snowboarder triggered a soft slab on an east aspect at treeline Thursday east of Loveland Pass (No one caught). This failed into our well known faceted grains. Dimensions were reported as 2' X 150 wide X 300 vertical.
Another human triggered slide was reported above Nymph Lake on a northeast aspect but we have no other details.
It is becoming increasingly difficult to travel off compacted trails near and below treeline as the snowpack continues to loose structure and weaken.
Moderate to strong winds continue Friday. Winds this strong tend to create greatest wind loading near treeline. The highest avalanche danger is hence near treeline on north through east to southeast aspects where human-triggered slides are likely. The snowpack is highly variable due to the winds. As widespread as the weak snow is, it is not everywhere, and some slopes have stronger snow. That means you will need to carefully evaluate the terrain and snowpack as you travel.
Harder, persistent slabs in the upper half of the snowpack are the secondary avalanche concern. You are most likely to find these slabs in highly wind affected areas above treeline. Many of these slabs are supportable in start zones, but become weaker down lower where you could trigger a large slide. Triggering a persistent slab is unlikely, but still a possibility. It is also possible for a smaller, wind-slab avalanche to trigger a deeper persistent slab resulting in a large slide that could bury you.