Vail & Summit County
AvalancheScott Toepfer · Dec 30, 2016 · Vail & Summit County
Weather
Clouds increased from just a few to high overcast by mid-afternoon. Some classic 'Mare's tails' cirrus early morning. A rather mild day. About 10 degrees warmer at the start of our tour, compared to the same time yesterday. SW winds were increasing in exposed areas.
Snowpack
Snowpack was again quite variable. Northerly NTL we found facets to ground in places, then onto a breakable wind crust, then to a pencil hard supportable windboard, and back to barely supportable faceted snow, all within a short distance of each other. At lower elevation near surface facets rested on a variety of (un-)supportable underlying snow. Sunnier aspects appear to be loosing volume to sunshine and mild temperatures. Generally a breakable suncrust with little if any slab character.
Avalanche
A very steep couloir with a large cornice at the top. In last 24 hours something caused the cornice to collapse (The cornice crown face was 275 cm--9 ft thick). The avalanche ran well out into a flat meadow. Very large cornice blocks survived the run. It would have been hard to survive this avalanche.