Location: Crested Butte Area
Date of Observation: 03/05/2018
Name: Ben Pritchett
Subject: Transitions
Aspect: North East, East, South East
Elevation: below treeline
Avalanches:
Weather: Cold front rolled in at 1pm as advertised. Bluebird to Blizzard.
Snowpack: Dug in the heat of the day (late morning) on a sunny southeast aspect and found the snow surface was actively generating free water that was percolating down about 3 inches. That wetting front will be frozen for a few days, but the spring transition is beginning. On those some southeasterly aspects, we observed a facet layer down about 8″ that will be our first layer of interest as we start to track wet snow concerns in the coming week. Compression tests popped cleanly on these facets, and if wetted, would be a perfect weak layer for shallow wet slabs. In higher elevation terrain or wind drifted terrain with more load on these southeast aspects, we’ll need to watch these buried facets layers as water percolates down to them. The set up for wet slabs this spring is looking ripe.
As we transitioned to easterly aspects, the free water had only formed thin surface crusts, no percolation below the snow surface.
Just a few degrees north of east, the snow surfaces were smooth and creamy with no sun crusts, still providing great turns.
As the sun returns after this cold front, it’ll be time to start hunting the aspects. Profiles on the shady side of east produced sudden collapse results on our pre-February facet layer (our Persistent Slab concern) and near the ground on depth hoar (our Deep Persistent Slab problem). The structure is still lurking, we’re just lacking the big loading event so the below treeline problems are in hibernation.
Photos:
Rills (technically not runnels) forming on the snow surface showing free water draining down into the snowpack. The first sign of our oncoming spring transition.