Northern San Juan
SnowpackAmy Pertuz · Apr 10, 2023 · Northern San Juan
Weather
Clear skies with light winds. Rapid rise in temperature before noon.
Snowpack
Easterly slopes remain the most concerning moving into a warmup, with percolating water still within the top 75 cm of the snowpack near treeline, and some facet-crust interfaces showing signs of saturation. The most concerning interface was the upper of the two facet-crust layers which formed at the end of March and are buried from 40-50cm and from 55 to 65cm deep on southeast and east aspects near treeline. A profile on an east aspect at 11,400ft yielded planar results and propagating failures in snowpack tests at a moistened interface above a thin crust buried 50cm below the surface. This would be a concern for wet slab activity on near-treeline east aspects moving into Tuesday. Southeast aspects near treeline show signs of melt-freeze cycles down to about 80cm deep, while easterly slopes still harbor transitioning cold snow which is just starting to see more percolating water. At this elevation, the dust layer from the beginning of April is still not exposed on the surface to accelerate the meltdown, but I expect southeast aspects to have brown-tinted surfaces within the next day or two, and a much faster meltdown resulting. Above 11,800 feet, cold surface snow predominated, and northeast aspects still have a winter character. On a northeast aspect near treeline at 11,800 feet, I found about an inch of dry surface snow, with decomposing and fragmented stellar snowflakes still visible, with four inches of moist snow below above small dry grains. The variety of snow types- dry, moist, small-grained, large-grained, wintery or springlike- is the greatest across short distances near treeline on easterly aspects. Slopes with cold, dry snow wit adjacent to slopes with a mix of dry and moist snow. Overall, there was not much wet activity prior to md day Monday, except the lower elevation south and west aspects.