Vail & Summit County
AvalancheBill H · Mar 5, 2017 · Vail & Summit County
Weather
Sunny, warm; moderate-strong west winds on ridge lines
Snowpack
W-facing ridgetops scoured. Rapid new cornice growth on E-NE aspects. Small-medium wind slabs, 6-12" thick on E-NE aspects both at ridgeline and below ridges on aprons. 1F+ to P hardness on surface, grading down to 4F sitting on top of a harder bed surface; probably just multiple layers of wind slabs sandwiched below but I didn't dig any deeper. On a small test slope I was able to propagate fractures along a cornice line for ~5 meters+ at a time without much effort, and get smaller blocks to trigger localized portions of the slope beneath the cornice. Protected areas in the valleys are developing near surface facets (skiing is improving on old wind/sun affected snow). Southerly aspects on the way back to trailhead that were out of the wind warmed enough to start getting wet by 1:30 pm.
Avalanche
N/NC-HS-D1.5, NE wall of Mayflower Hill. Due to localized wind patterns, looks like wind slabs have formed well below ridge lines here as well. This slide propagated across the aprons of several steep chutes below a cliff band. Path was wide (80-100m) but short (15m+). The freshness of debris and crown made it look recent; last 24 hrs. Most likely guess for trigger was a cornice drop from above.