Northern San Juan
AvalancheKrista Beyer · Mar 23, 2024 · Northern San Juan
Weather
Winds picked of from the southwest as forecasted. Despite the wind, temperatures remained mild and warm. Notably nearby weather stations showed a mild freeze overnight on the 22nd.
Snowpack
On easterly aspects snow surfaces were warm. If storm comes in warm as expected, snow will likely bond well to these surfaces. On northerly aspects surfaces were noticably denser than in previous days. This is likely due to increased winds drifting snow into an orange peel surface and warm temperatures effecting all aspects at lower elevations. Some near surface faceting on due north aspects may interfere with bonding of the new snow. I dug on an east aspect near treeline. Height of snow locally was 125cm. The top 15 cm of the snowpack contained layers of melt-freeze crusts the most dense of which sits at the visible dust. Percolation columnes were visible all the way to the top of the basal facets. The whole snowpack shows signs of rounding which was observed in the density of the snow while shoveling. Weak layers in the upper pack are related to facet growth beneath crusts and changes in hardness (CT11 @ 110cm, and CT14 @80cm). None of these layers indicate propagation propensity (ECTN12 @110cm and 23 @80cm). Some pooling observed around the 80cm weak layer that divides a finger hard slab from a pencil hard slab.
Avalanche
A small skier-triggered slide on the 22nd on a NE slope was isolated to the surface snow. Winds late on the 21st may have drifted enough snow to form small wind slabs in isolated areas. It appears as though a small surface slab was the culprit for entraining dense snow down the slope.