Professional Observation

Observation Details

Signs of Unstable Snow

Key Points

I toured in Rock Creek, where the snowpack is shallower, to track the sensitivity of the persistent slab problem.

• Near treeline, at 11,100 feet, I triggered long shooting cracks and a big collapse from 40 feet away. (See video above) I got several more collapses and cracks up to the ridge line where the persistent problem is spottier because of wind scouring and deposition.
• Though I saw some tufts of blowing snow in the morning, there was less wind than forecast. I only found small, unreactive wind slabs near the ridge.
• It was cold. That will likely keep the buried weak layers from healing in areas where the snowpack is the shallowest.
• The areas that concern me most for the persistent slab problem – which hasn’t gone away yet – are areas with shallower snow cover adjacent to thick, hard slabs. If you can initiate a failure in a continuous layer of buried facets, they can propagate that failure across a slope.

I initially started my day planning to cautiously step out towards steeper terrain. Now I’ll continue to check my slope angle in terrain where I find a stiffer slab over the persistent weak layer that’s buried less than a meter from the surface.