CBAC 2020-21 Observations

Zone: Southeast Mountains

Location: Coneys

Date of Observation: 12/13/2020

Name: Jack Caprio

Aspect: North, North East, East

Elevation: 10,800


From the ridgeline, skier remotely triggered a R1D1.5 persistent slab on a NE facing aspect near the treeline. The avalanche broke on a 1-inch thick melt-freeze crust about 14 inches down from the surface. Above the MF crust were 1-2 mm faceted grains which developed during our dry spell before Thursday. The slide entrained all the new snow from the most recent storm (about 14 inches) and propagated about 60 feet wide. The slab initiated on a > 30-degree start zone and the momentum quickly diminished as the slope angle decreased. All in all the avalanche ran about 150 vertical feet.


Weather: Sunny and cold. Very subtle to no winds along ridgeline at 2 pm.

Snowpack: Last night’s winds towards the tail end of the storm cross-loaded many slopes. In open areas, the surface snow of breakable windboard ranging from 1-3 inches made for some very unenjoyable turns. Underneath the windboard was about 10-15 inches of F+ storm snow. On N aspects, basal facets made up the bottom foot of the snowpack. As soon as the compass rotated east of north, a melt-freeze crust with near-surface facets above it was found sitting below the new storm snow. This melt-freeze crust was the guilty layer/ bed surface of the skier triggered slab.