Ski Tour: IMB > Eldorado Test Slope > Martin Mine > Granite Mountains Tailings > Cross Hill
2/8-9: Strong winds mainly from SE at Marmot anemometer. Winds transported snow, building slabs, which overloaded the snowpack and resulted in widespread avalanche activity.
Numerous recent natural slab avalanches. We generally observed more connected avalanches, but shallower, on Southeast to Southwest aspects. Less connected, but deeper on NW to E aspects. Many D2 size avalanches, with a few D2.5. Marmot paths were up to D3 (larger destructive force due to terrain trap), and one avalanche off of Marmot was D3 which crossed the Archangel groomed ski trail.
Two avalanches off of Marmot just barely crossed the road, requiring DOT to close the road for a short period of time on 2/10 to clear debris.
|Cracking (Shooting cracks)?||Yes|
Widespread recent avalanches.
No whumphing on our tour, with only localized cracking. Very thick hard slabs, up to a meter thick, were supporting our weight without cracking or collapsing. We suspect these slabs could fail under a person weight in thinner, weak, specific locations due to variations in slab thickness, and that propagation would be significant.
Wind deposited slabs in protected areas and valley bottoms were up 6-12" thick, upside down, sitting on soft precipitation particles.
Approximately 1.3” of SWE in this storm and 13”+ inches of new snow (difficult to assess in the field due to wind effect).
3100´: Clear, Light Northerly winds, Temps 3 warming to 10 in afternoon
Wind effected snow, 4F to P, wind broken particles, graupel.
Crown profile on Eldorado Test Slope, E, ~3400', 43 degree slope, revealed 1 Finger to Pencil hard, 115cm/45" slab, failing on Fist hard 1/29 facets. ECTP14
Deeper in the snowpack I observed the earlier January facets which did not fail in this avalanche.