Northern San Juan

Avalanche

Bill Nalli · Feb 28, 2021 · Northern San Juan

Weather

Very strong SW wind gusting into the 50's and 60's on Feb 27 eased into the moderate category mid afternoon. Fresh wind drifts formed in exposed terrain on east through north-facing slopes. Clearing skies overnight, calm wind and single digit temps began Feb 28. A trace to 1 inch of new snow was observed over the weekend.

Snowpack

The warming from the week of Feb. 22 has locked up and created a sun crust that varies from breakable to supportable on east thru south-facing slopes at all elevations. Shallow fresh wind drifts exist on east thru north. Several exposed ridgelines look to have formed slabs deep enough to pose a new threat to riders. Windward aspects are a mix of moonscape-like sastrugi and bare ground. Sheltered terrain facing the north half of the compass still harbors soft settled powder about 10cm deep. This sits above a dense 1F layer 20 to 50cm thick all resting on a sinister layer of facets and depth hoar. See pics of 4mm DH on NE aspect at 10,000'.

Avalanche

Lots of avalanches seen on every aspect and elevation. Unknown timing. Some from Feb 18 time frame, Feb 22 warming, and possibly Feb 27 from wind event? Specifics best left to those more intimate with recent events than I. Very widespread cycles.