|Fri, February 2nd, 2024
|Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
|Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
|Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential.
|Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
|Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain.
|Likelihood of Avalanches
|Natural and human-triggered avalanches unlikely.
|Natural avalanches unlikely; human-triggered avalanches possible.
|Natural avalanches possible; human-triggered avalanches likely.
|Natural avalanches likely; human-triggered avalanches very likely.
|Natural and human-triggered avalanches certain.
|Avalanche Size and Distribution
|Small avalanches in isolated areas or extreme terrain.
|Small avalanches in specific areas; or large avalanches in isolated areas.
|Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas.
|Large avalanches in many areas; or very large avalanches in specific areas.
|Very large avalanches in many areas.
~Several parties on Wednesday 1/31 were able to trigger sluffs in steep terrain. One individual on Microdot triggered a large loose dry avalanche on a south aspect at 4500 feet in elevation that ran about 300 feet.
~Natural loose dry avalanches were observed on numerous different aspects in terrain steeper than 40° that were small to large in size (D1 to D2).
|Size (D scale)
|Unlikely to bury a person
|Can bury a person
|Can destroy a house
|4 & 5
|Can destroy part or all of a village
A relatively efficient and chilly storm refreshed the slopes of Hatcher Pass with 6 to 8 inches of low density snow on January 28th & 29th. The cold ambient air temperature and initial lack of wind resulted in an evenly distributed layer of unconsolidated new snow. During the day on January 29th light to moderate winds began to transport the new snow. Luckily the duration was short-lived and only a minor surface wind skin formed on leeward aspects facing southwest through northeast. This wind affected snow is 1 to 2 inches thick and slabs are small and disconnected. It is unlikely that this thin surface layer will propagate failures resulting in a large avalanche.
As the skies cleared and people began pushing into steeper terrain, some natural and human triggered loose dry avalanches (D1 to D2) were visible. Most of the avalanches are small and easy to avoid but a few are a bit larger in size and entrained much of the 6-8 inches of new snow. Debris and evidence of this avalanche problem can be found on all aspects at the mid and upper elevations. Some point releases originated from rocky outcrops, convexities, and in locations where previously firm surfaces exist. Terrain traps and gullies are places where it is possible to trigger a dry loose avalanche and a likely place someone could get caught and buried.
Prior to the storm a 15 day dry spell, with some cold and clear conditions allowed the snowpack to facet-out older stiffer layers. The result was a mostly stable snowpack with areas of firm surface snow near windswept ridgelines. Currently slopes steeper than 40° are the most susceptible to triggering small to large loose dry avalanches. Many of these sluffs are slow moving but can entrain enough snow to bury or injure a person, especially on southern aspects where firm bed surfaces are present. We recommend avoiding terrain traps, riding one at a time, using appropriate safe zones, and sluff management techniques. As the clear and cold conditions persist expect surface snow to remain reactive and the dry loose avalanche problem to continue.