Gunnison

Snowpack

Zach Guy · Jan 17, 2012 · Gunnison

Weather

Temperatures rose to near zero at ridgetop, and single digits at the lower study plot. Ridgetop winds were moderate from the SW, gusting to strong and extreme. Moderate snow transport. Skies were clear. Storm board has settled to 10" (but has likely been affected by winds)

Snowpack

Explosives and ski cuts produced several soft slab avalanches on west facing terrain near and below treeline. Slabs were contained within specific terrain features, without wide propagation (mostly R1, R2). Several stepped down below surface crusts and entrained faceted snow below; sizes were D1 to D1.5. Snowpack on W through S through SE at and below treeline consists of basal facets and/or crust and facet sandwiches buried by the recent windslabs. We experienced rumbling collapses below these crust layers, particularly in flatter terrain where we had not previously ski packed. The fresh windslabs are quite variable due to varying wind patterns; scoured in some areas, up to 50 cm in others, and only appear to be consistent in protected terrain near and below treeline. Cracking from explosives and ski cuts was widespread, mostly contained to the new windslabs but in some areas penetrating into older layers. We observed fresh crowns from natural activity on the saddle of Ruby/Owen (E facing, R2D2), Mt Afley (SE facing, R3D2), Ohio Peak (NE facing, R2D2), all above treeline and they appeared to run on the interface below the storm snow. Further evidence of mid-storm cycle avalanches on NE and N aspects on Scarps Ridge. Below treeline, numerous R1D1 slabs released on steeper terrain. SW alpine terrain was heavily scoured in most areas.