Vail & Summit County
AvalancheJason Konigsberg, Ryan Zarter · Jan 16, 2018 · Vail & Summit County
Weather
Cold start to the day with single-digit temperatures. Temperatures warmed to the teens and it felt pleasant in the sun.
Snowpack
Today we went from Vail ski area out to the East Vail backcountry looking for recent avalanches and also to determine what layer these avalanches are breaking on. We dug on north to east slopes near treeline. With remarkable consistency we found the weakest snow to be the top of the depth hoar layer which is anywhere from 20 to 40 cms from the ground. This is the layer that many of the avalanches in the East Vail area are breaking on. We found it hard to identify the layer of facets that formed in mid-December. Where we did find this layer it was strong and any test results on this layer were not alarming. The depth hoar is a different story. ECT results showed propagation but often after over 20 hits. PST results were consistently 30/100 END. CT results were always easy. This soft layer of fist-hard DH may be increasingly harder to trigger but it is not going away anytime soon. We can characterize all slopes in this area in two categories- First- The slope has already slid. Second- The slope will slide eventually. It is hard to imagine a scenario where these slopes with poor structure don't eventually avalanche, either with a human-trigger in the wrong spot, or a significant load.
Avalanche
We saw numerous avalanches today many of which were at least a few days old. Three to four crowns were observed around the Marvin's area of East Vail. All avalanches look to have broken on depth hoar layer. We saw a significant older full-depth crack below the upper cliff band that ran a few hundred feet. It seems that this areas was really close to seeing avalanches run wall to wall during and immediately following the last storm.