Northern San Juan
AvalancheChris Bilbrey · Feb 14, 2024 · Northern San Juan
Weather
A mix of overcast-obscured skies in the morning with very light snow flurries. Today's snowfall didn't amount to measurable accumulations. Progressive clearing during the day with partly to mostly clear skies by the afternoon. Moderate southwest winds efficiently moving snow onto northerly and easterly lee's. Temperatures felt average for the time of year.
Snowpack
Snowfall during the first half of February really boasted snow coverage in this portion of Molas Pass. We found mostly supportive over-the-snow travel across multiple aspects and elevations, but a subtle trap-door feel still exists in shallower, wind-scoured places near and below treeline. However, these places have become fewer and far between. Depth of boot penetration has decreased dramatically and impacting deeper weak snow layers likely needs to find the shallow spot on the slope. The primary weak layer of concern is the January 4 interface - especially at upper elevations where a pencil hard slab sits above 4F large grain facets and depth hoar. While this interface is now buried under a meter or more thick slab, individual grains appear slow-to-heal. We were able to identify the 2/2 and 2/6 interfaces on multiple aspects, but they did not strike fear in today's snowpack tests and were unreactive to stubborn at best. The weight of the most recent storm slab appears to be helping squash these thinner interfaces. Despite a stout slab above weaker snow layers, ECTs in our northwest-facing alpine pit still propagated a crack with 25 taps, and CTs failed with 7 taps. The column dropped around an inch when sudden collapse failure occurred. Digging on a southwest-facing slope adjacent to several natural slides, we observed stubborn, non-propagating results in ECTs in a thin layer of near-surface facets around 35 to 40 cm deep. We did not dig below treeline, but we could easy punch through to the January 4 interface while probing and depths were consistently between 90 and 100 cm. Only a couple audible collapses, and they occurred on a shallow part of a southeast-facing slope with weaker facets above a crust below a harder slab.
Avalanche
Lots of evidence of mid-storm avalanche action from the 2/6-9 storm event with most crowns filled in but debris piles still visible on the landscape. Only one small, fresh-looking Wind Slab avalanche on a southeast-facing slope below the ridgeline.