Southern San Juan
SnowpackChris Bilbrey · Mar 23, 2022 · Southern San Juan
Weather
The wind was fierce and angry today above treeline. Snow being transported was sublimating more into the atmosphere than efficiently loading onto leeward slopes. Lower in the terrain, the wind was confused with micro-terrain features creating eddies and upslope conditions around the compass. No slope spared from wind-damage.
Snowpack
Today's wind kept surfaces cold and locked up around the compass and all elevations. The exception was southerly-facing slopes below about 9,500 feet, but those areas pose little avalanche hazard from depletion of snow cover and limited new snow in recent weeks. The wind blew hard enough that wind-slab formation remained isolated with respect to the broader area. Where we did find fresh slab formation, it was generally an inch or two thick and stubborn to ski pressure. Warming temperatures over the next couple days should eliminate this problem where it does exist. Digging on northerly-facing slopes near treeline confirm the general trend toward unreactive behavior in the "drought layer" facets. Those facets did not fail in snowpits dug on a north-northwest aspect. However, a thin layer of faceted snow around a foot deep produced break failures with moderate force in Compression Test. As the overlying slab becomes moist during the warm-up, it could be more likely to fail from the extra push of a rider as a loose wet slide, especially on slopes steeper than about 35 degrees. In the alpine, north wind pressing and stiffening the snow surface may make triggering a slide in older, weak snow less likely. Still, shallow areas do exist in the alpine and where a rider is more likely to impact weaker snow below - but this likelihood seems to be on the downward trend as well. A snowpit on an east-facing slope at treeline yielded 4F, dry to moist facets, resting between two stout crust. These softer grains are close enough to the surface that once water gets moving into the snowpack, Wet Slab avalanches could initially fail in this layer, propagate wide, and gain speed moving down the slope with a firm, slippery crust below.