Soldier & Wood River Valley Mtns

Strong winds and new snow built thin, stiff drifts in terrain exposed to the wind yesterday. In areas sheltered from the wind, generally stable avalanche conditions exist. Sluffs in the sugary surface snow are possible on very steep slopes at lower and middle elevations.

There are no well-defined avalanche problems in this zone, but here are a couple of potential hazards to keep in mind:

Wind Slabs: Yesterday's weak storm brought up to two inches of snow to this zone. This combination built very small but sensitive and stiff drifts in terrain exposed to the wind. You may find these slabs in atypical locations, such as in middle elevation terrain that is generally sheltered from the effects of the wind. Though these slabs are small and isolated, they may be large enough to knock you off your feet and carry you through some unpleasant terrain. Be alert to the consequences of triggering one of these thin slabs if you are traveling in steep, rocky, heavily treed terrain.

Persistent Slabs: Weak, faceted snow exists near the base of the snowpack. I was traveling in the East Fork of the Big Wood drainage last week (near the boundary with the Galena Summit and Eastern Mtns Zone) and saw evidence of many slides that failed on this snow during our last major storm (you can view my observation and avalanche report here). You're most likely to find this weak snow on shady slopes above about 8000' in elevation—especially in the deeper snowpacks near Dollarhide Summit towards the Soldiers. Triggering an avalanche on this layer is unlikely, but not impossible. You're more likely to find trouble on slopes with the following characteristics:

• Steep: slopes steeper than about 35 degrees.
• Rocky: slopes with variable snow cover due to the roughness of the terrain.
• Wind-affected: slopes where strong winds produced variable snow cover.

Loose Snow: The ongoing dry spell and temperature inversions have produced a thick layer of cohesionless facets on shaded slopes at middle and low elevations. As the snow surface turns to sugar, it becomes increasingly possible to trigger loose snow slides—sometimes called "facet-lanches".  Last week, a skier was knocked off their feet by one of these sluffs (observation). Once moving, this cohesionless snow can gain a surprising amount of speed and mass in very steep terrain. 

You can quickly catch up on what happened this past week in my latest Weekend Update video.