Northern San Juan
AvalancheKrista Beyer · Apr 2, 2024 · Northern San Juan
Weather
Day started cool and overcast. It took all of 5 minutes for the sun to pop, the skies to clear and surfaces begin to heat. Surfaces include loose rocks on steep cliffs, watch out above! Temperatures climbed to just above freezing near 12,000ft at nearby weather stations.
Snowpack
The snowpack can generally be described as 'right-side-up' recent snow stacked above a thick, strong mid-pack slab above early season facets. At the parking lot level, snow coverage is generally thin, and southerlies are spotty. Climb up a few hundred feet to 10,000 ft, and the snowpack is a meter deep on flat road surfaces. There are multiple weak layers in the upper pack. They are thin and quickly appear to go unreactive under warming trends. Weak layers can generally be described as faceting under crusts or buried near surface faceting, depending on the aspect. Getting into the details: We dug on an east and northwest open slope near the treeline. The east pit location was a more shallow feature. Multiple crust layers exist in the upper pack that are unreactive to tests. We received our first propagating result in quite some time on buried facets at the ground (ECTP26, CT11 (SC)). The test result shows that the basal facet structure exists, but snowpack trends indicate that these locations are isolated to specific terrain features and are generally hard to impact. A non-standard ECT of 120cm long column produced no results (ECTX). In our northwest pit, we found a buried layer of near-surface facets that is the likely culprit for recent avalanche activity on similar slopes. This layer is thin and reactive on compression tests (CT13 (SP)), but not ECT (ECTX). This layer likely developed around March 23rd, prior to the last two snow events. On that day, strong winds created a reactive wind slab on specific north aspects (particularly observed in the Telluride area) despite a recent warming trend and two nights of superficial freezes.
Avalanche
Loose wet avalanche activity graced the mountains. Loose activity was limited to steep terrain out of cliffs and rocks.