Vail & Summit County

It looked like a recent avalanche in Deer Creek. Also, a decent-sized avalanche in an east-facing path adjacent to the Maid of Orleans path. Debris looked fairly fresh at the bottom of the path (see photo).

3 inches of new snow and strong west to northwest winds. It was cold in the morning, but warmed nicely under the afternoon sun.

I dug on a couple of northerly slopes near treeline, which are among the most likely places for Persistent Slab avalanches. At the sites I investigated, there was little recent drifted snow, so stability was relatively unchanged with the small amounts of new snow. The snowpack on these slopes is 105 cm deep. A one-finger–hard slab is present in the mid-pack, about 55–80 cm above the ground. Beneath this slab is weak faceted snow, with the weakest and softest layers around the pine-needle layer from the December 17 wind event. As we’ve seen in other areas, the February drought layer has strengthened, while the early-season layers remain the weakest. It is difficult to initiate a crack in these deeply buried layers, with Extended Column Test results of ECTP28. Propagation Saw Tests are still showing relatively short cut lengths (25/100 end and 30/100 end), indicating high propagation propensity. These results line up with recent avalanche observations: avalanches are few and difficult to trigger, but could be large and wide. I also dug on a west-facing near treeline slope to see how much water has infiltrated the snowpack from our last warm-up. I found that the upper snowpack was flooded (now frozen) with percolation columns (or preferential flow tubes) from the midpack through the basal facets to the ground. The faceted snow around these flow tubes was still dry. On south-facing slopes near and above treeline, melt-freeze crusts are thick and impenetrable under the few inches of new snow. As soon as you change aspect to a more westerly or easterly direction (from south), crusts become a little more breakable and the snowpack is more faceted with fewer signs of recent water moving through the pack.