Schuylkill Ridge

Our goal for the day was to check the sensitivity of wind-drifted slabs at upper elevations and Loose Dry avalanches in sheltered areas. 

We experienced several small collapsed and shooting cracks on recently formed slabs below the ridge top (see image).  Slabs were up to 12 inches thick and extended around 30 feet down slope.  Neither slope released, but it was clear this avalanche problem remains sensitive to a person's weight.  We walked along the ridge to find a sheltered entrance into the terrain and avoided traveling across the stiff surface slabs.

In sheltered terrain, we released several small loose avalanches on steep slopes.  Not all steep slopes were weak enough to produce a loose avalanche, but many were.  We used defensive ski techniques on the descent by moving across the fall line to manage the moving snow.

While walking across Schuylkill Ridge, we collapsed and cracked several drifted features immediately below the ridgetop. Neither slope released.

At ridgetop, thin slabs formed from previous winds wherever an open fetch existed on the windward side.  Slabs felt up to 1 finger hard and likely supportive to skis (we didn't ski across).  Although the slabs are not very thick, up to 12 inches, they are stiff enough to transmit failure and produce an avalanche that you don't want to be in. Cracking and collapsing suggest this is a problem for people to avoid.  We could identify these locations by open fetches, cornices, and smooth, stiff textures.

In sheltered areas, the snowpack ranged from 45 to 70 cm deep.  The variation in depth is likely related to timing a given slope avalanched during the Thanksgiving natural cycle.  Slopes that avalanched earlier in the cycle had more snow.  Slopes with depths of around 70cm were less likely to produce a loose avalanche, and shallower snowpack slopes were more likely.  The shallower the snowpack, the weaker it was.