Vail & Summit County

Avalanche

Jason Konigsberg, Ron Simenhois · Mar 17, 2021 · Vail & Summit County

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Weather

Cloud cover decreased by afternoon with patches of clear sky and the strong sun impacting the snow surface on sunny slopes.

Snowpack

No obvious signs of instability were observed today. Upper PWL layers are something to monitor but they don't seem to be reactive right now.---Details-Recent snow, from about the last 7 days, is about 40 to 50 cm (16 to 20 in) in this area. Snowfall over the last 24 hours was 10 cm or 4 inches. The slab of new snow has settled and is up to one-finger hardness above a recently buried persistent weak layer. On north-facing slopes this persistent weak layer is .5 to 1 mm faceted crystals. We got a result of ECTP21 in an extended column test on this layer 47 cm from the surface. The total snow height was 180 cm. The block slid very easily when pushed off of the column. On most other slopes, the recent snow sits on a crust/facet combo. We dug on a below treeline slope and found recent storm snow of 35 cm. This snow was totally dry with no noticeable affects of recent, brief periods of warming. We got a result of ECTP16 at 40 cm from the surface. The snow height was 140 cm on this slope. On our exit the snow surface on this slope was becoming moist from the afternoon sun.

Avalanche

We checked out the recently reported avalanche off of the shoulder of Mt Guyot. The crown was fully filled back in, so it was tough for us determine what the avalanche failed on. We were able to confirm that it broke in the upper snowpack and not near the ground. Where the avalanche ran, there was still at least a meter of snowpack left. Weak depth hoar, about 10 cm thick, rests near the ground. Best guess is this avalanche failed on the most recently buried facet layer. This was during a time of intense wind loading, so not really indicative of the sensitivity of other slopes at present.---We observed several small avalanches on easterly-facing slopes off Bald Mountain. For these avalanches to run and not trigger anything bigger is another sign of a strengthening snowpack.---One loose avalanche observed in the Monroe Path in Tenmile Canyon. Triggered by snow shedding from cliffs with afternoon sun.