Northern San Juan
AvalancheKrista Beyer · Mar 26, 2024 · Northern San Juan
Weather
Red Mountain Pass to the south and Monument study plot to the north picked up 18" and between 1.25-1.65" of SWE since 3/24. A reported 6" or .5" SWE fell throughout the day and overnight at those study lots. Winds over the past 24 hours averaged 5 mph NW with a peak gust of 22mph at nearby Mount Abrams weather station. The highest recent winds were a day prior to the storm on the 23rd out of the SW (average 14 mph with a peak gust of 50mph). Weather stations to the south and slightly higher in elevation show higher recent wind averages N and NW in the 15 mph range. Temps have remained cold.
Snowpack
I traveled on west-facing terrain between 9,700 ft and 11,750 ft. Height of new storm snow was about 10 inches at the lower elevations and 15 inches at the upper elevations. I dug on a WNW slope near and below treeline and observed a weak breakable crust 1.5 cm thick under the new snow. This surface was slick for steep uphill travel, but unreactive during downhill travel. I observed no cracking or slab formation in the new snow near or below treeline, and any movement in the new snow was limited to small sluffs on slopes over 38 degrees. Near treeline I observed moderate broken failures above and below this crust during compresion tests. Below treeline I observed no failures on this crust during compression tests, but moderate planar failures on the basal layer. No propagating results were observed in either location. The near treeline snowpack is 165cm and contains a strong thick cohesive slab. Below treeline the snowpack is 120 cm and is weaker and feels rotten. No signs of percolation columns were observed at either location, but, at lower elevations clustered rounded grains were observed throughout all but the basal layer (and evidence of rounding facets here) indicating that water has moved through the entirety snowpack. Less water has moved near treeline, but clustered rounded grains could be found in the top 40 cm of the pack prior to the most recent snowfall.
Avalanche
Hard to tell when this avalanche occured, lumping it in with a small natural cycle I observed during the last storm.