Vail & Summit County

Avalanches during the storm in the Monroe and Ponds paths in Tenmile Canyon

Warm and calm. No snow transport observed. The top inch of west-facing slopes was getting wet.

On below treeline west and northwest-facing slopes I got a score of ECTP13 in extended column tests. On the west-facing below treeline slope, I also got a score of 35/100END in a propagation saw test. Although the crack propagated to the end of the block, when I moved the block with my shovel, the slab fractured in half. This tells the story of the snowpack below treeline having a slab that is barely cohesive enough to communicate a fracture. I didn't on travel on any wind-loaded below treeline slopes. I would imagine that these types of slopes are much more likely to produce an avalanche. Below treeline slopes are just entering a Persistent Slab avalanche problem, but are still in the youth stage. We are far from seeing peak BTL avalanche potential with this horrible snowpack, but we will need more snow and more slab building to get there. Near treeline slopes are a totally different beast than lower elevations. February storms built a thick, cohesive slab even on previously scoured northwest-facing slopes. The snowpack is deeper than BTL, with thicker, more cohesive slabs that propagate fractures in tests with the same number of taps (or fewer) than lower elevations. Where I dug, the snowpack was 120 cm deep, and the slab was 40 cm thick. The bottom half of the slab was solid, with one-finger hard snow. This hard, settled snow is from our mid-February storms. For once, storm snow settled into a slab instead of faceting away before the next storm (the 2/25 storm). One of my goals today was to evaluate west-facing slopes for inclusion in the forecast Persistent Slab distribution. West-facing slopes below treeline are really borderline. Slabs are thin and the upper snowpack is warming each day, leaving hard crusts in the morning. These slopes certainly aren't the most likely place to trigger a Persistent Slab avalanche, but if you found the wrong open, crossloaded slope, it's not totally out of the question. It's not much different near treeline on west, though the snowpack is a little deeper and colder. I think once thick crusts form and are buried by light snow loads, these slopes will also be much less likely than other aspects/elevations on our Persistent Slab distribution.