Southern San Juan
AvalancheChris Bilbrey · Jan 25, 2022 · Southern San Juan
Weather
Sunny skies and a few high clouds through midday gave way to lowering clouds and light snowfall by 2:30 pm. Winds were generally light along alpine ridgelines.
Snowpack
Snow surfaces remain firm and variable across many aspects and elevations. Southerly-facing slopes near and above treeline have a firm 2 to 3 inch thick crust on the surface that was supportable to ski and foot travel. In wind-sheltered areas on the same slopes and elevations, surface crust was thinner, not as robust and a thick layer of near-surface facets developing below the crust. Where the crust was breakable, we sunk around 10 to 15 cm's below the surface while booting uphill. On the flip side of the compass, northerly slopes above treeline are a mixture of hard wind slabs adjacent to softer textured snow surfaces found in protected areas and on leeward sides of terrain features or gullies. A common theme we found, lower-angled slopes offered softer conditions in the alpine. Northerly-facing slopes near and below treeline offer the best odds to encounter soft riding conditions, but evidence of wind-stiffening and punchy conditions observed well below treeline. We dug on a north aspect near treeline and found a generally deep and strong snowpack. Facets/ depth hoar at the ground are getting harder, rounding and very stubborn to fail in test. These concerning grains are buried below about a 150 cm 1F to Pencil hard slab with no discernable weak layers/ interfaces, or failures in the top meter. Lots of near-surface faceting on the surface that could be susceptible to failing under a larger, new load. East and west-facing slopes harbor a crust/ facet combination at upper elevations and those same slopes below treeline have been tormented by a month of warm, dry weather. Slopes around 10,000 feet where snow depths are around 2 feet deep or less are becoming rotten and pole probing easily broke to the ground without much effort. This is most obvious on the southern half of the compass. Northerly-facing slopes around 10,000 feet still felt solid, but the upper slab is slowing degrading.
Avalanche
No new activity observed. Numerous old crowns on northerly-facing slopes near and above treeline that most likely ran around the New Year. Size hard to make out due to evidence drifted/ filled in.