Northern San Juan
AvalancheColin Mitchell · Mar 9, 2024 · Northern San Juan
Weather
Bluebird day with rapidly rising temperatures and light northerly winds. Intense solar radiation was starting to moisten upper layers at my profile site even with below freezing temperatures.
Snowpack
I targeted south and southeast near-treeline slopes, similar to the start zones in nearby highway paths. Height of snow averaged around 150 cm. Snow storms interspersed with some very warm days have created complex layering in the upper 60 cm of the snowpack. Several crusts have formed as well as a prominent dust layer. The mid-February facet layer is down about 55 cm. Three prominent crusts in the upper snowpack all produced easy to moderate Q1 failures with compression tests, but Extended Column tests did not produce propagation. Neither the February facets or the depth hoar at the base of the snowpack were reactive to tests. Melt water has begun to affect the snowpack. I found thin percolation columns between the upper and middle crust layer. The middle crust is down about 20 cm. Melt water has been pooling here, is starting to turn the crust into a thick, ragged ice mass. Pole probing on northerlies during my ascent revealed a simpler structure in the upper snowpack, with about 25 cm of fist-hard new and recent snow over a thick, pencil-to-knife hard slab that became harder with depth.
Avalanche
No new activity observed