Southern San Juan

Avalanche

Chris Bilbrey · Mar 12, 2020 · Southern San Juan

Weather

Warm and sunny day with generally light winds. High thin clouds moved in during the afternoon signaling the beginning of our upcoming storm system.

Snowpack

We found about 8 inches of snow that has fallen since 3/8. Today's weather of warm temperatures, a strong sun, and light winds kicked off a major shed cycle of recent storm snow. Most of the loose sluff piles were small except where constricted in gully features - roller-balling galore. We saw evidence of loose-wet slides on all aspects below treeline and east through south to west aspects near and below treeline. Activity in the alpine was very isolated. Sluffing was confined to recent storm snow and none that we saw created a slab avalanche. Isolated evidence of natural wind-slabs that failed during our last snowfall event - mostly on northeast and east-facing slopes. Those slides appeared to fail at the 3/8 interface. Weak layers still loom deeper in the snowpack and Extended Column Test confirmed this with propagating test results on layer of near-surface facets. Although it took a lot of taps to initiate failure (ECTP 21), these results suggest that if a thick new load is added above, avalanches breaking in old snow is possible.

Avalanche

More loose-wet slides than we could count. Most were size 1 but some inched close to size 2, especially where confined to a gully feature.