|Sun, December 24th, 2023
|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.
No recent avalanches were observed or reported on Friday.
On Thursday a few small human triggered dry loose and slab avalanches were observed on Marmot, Microdot, and Nosebleed. In addition, small natural slabs 5 to 10″ thick were observed on the west aspect of Skyscraper (Willow side) and the southeast aspect of Skyscraper (above the summer road). A large cornice chunk fell from Rae Wallace and can be seen here.
|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
Winter solstice brought better than average coverage for December with excellent skiing and riding all week. Expect a shift in conditions today due to winds overnight that gusted SSE 33 to 44 mph at 4500′ for the past 12 hours and 23 to 29 mph at 3550′ for the past 6 hrs.
Wind slab avalanches: Strong winds overnight and over the next 24 hours will continue to build wind slabs on West to North aspects (clockwise) at upper elevation. It will be possible to human trigger a 3 to 6 inch thick wind slab on slopes 35º and steeper. Expect wind slabs to increase in size throughout the day if strong wind persists. Wind slabs that form on either firm bed surfaces or recently formed weak sugary snow (NSF near surface facets from recent cold weather) will be more reactive and have the potential to propagate further.
Winds are not expected to be strong enough to build wind slabs more than a couple inches thick below 3500′.
Pay close attention to wind transported snow and avoid steep wind drifted terrain. Shooting cracks and sometimes audible collapses are indicators of instability. Look for hard snow sitting over weaker snow, smooth and rounded or lens shaped features.
Persistent slab avalanches: Few, small, shallow yet wide propagating slabs 4 to 6 inches thick were observed this week as a result of new snow 12/17-12/20.
With additional strong winds over the next 24 hours there is a lingering possibility that new wind slabs will fail deeper in the snowpack in the weak sugary snow sitting on firm surfaces. It will be possible to human tigger a larger slab in isolated locations that fails 6 to 12 inches deep, on all aspects, at mid and upper elevation on terrain 30º and steeper. Finding these isolated locations may be challenging. Probe pole tests, hand shears, and instability tests will assist in finding these layers.
Dry loose avalanches: Relatively few dry loose (sluffs) were observed over the past couple days considering that Hatchers received 10 to 17 inches of new snow since 12/18. The new snow resulted in some small naturals on 12/20 and a couple reported human triggered sluffs on 12/21. Winds overnight and throughout the day will make triggering a sluff less likely, however, triggering a small sluff in terrain 40º and steeper on all aspects, above 3500′ and in protected locations is still possible.