Observation: Wolf Creek

This morning we went for a tour around Wolf Creek Pass to look for weakening snow and wind-affected snow. We found a variety of snow surfaces, including surface hoar (flat crystals 3-5 mm, needles 3 mm) and soft snow in non-wind-affected areas, and a thin wind crust in wind-affected areas. Rime was also plastered to the north side of trees. We stopped to dig a pit on a NE facing slope at 9700', a slope similar to a recent avalanche on 11/12. The height of snow was 62 cm, and we found a solid 1F slab overlying weak snow halfway down the snowpack. While ECT results showed fracture and no propagation at both this interface and an upper-snowpack density change beneath the weakening new snow, the snowpack structure is poor (see SnowPilot image).

The recipe for an avalanche is simple. A slab overlying weak snow + a slope steep enough to slide + a trigger = avalanche. We found a slab overlying a weak layer, so we avoided slopes steep enough to slide. With cold clear nights in the forecast, we expect last week's snow to continue to weaken. Whenever it snows next, I will be very cautious and conservative in my decision-making.

A variety of snow surfaces in the backcountry. In some areas, we were able to find rime, surface hoar, and just weakening surface snow. Wind crusts varied by aspect, we found both breakable and non-breakable crusts. Areas protected from the wind hold soft powder.

Riming on trees on non-solar aspects.

 

Riming on trees.

 

Large surface hoar out of the wind zone.

 

Thin wind crust at 9700' on a NE aspect.