Northern San Juan
SnowpackChris Dickson · Jan 7, 2025 · Northern San Juan
Weather
Light snowfall, cold temperatures, most calm with the occasional light gust.
Snowpack
The snowpack is growing deeper, but remains quite simple in its layering, especially below treeline. The top of the snowpack is comprised of a slab of newer snow that began to grow on 12/25 and is still growing. In many sheltered areas, this slab is fist-hard and lacks cohesion. The bottom half of the snowpack is comprised of well developed facets (the "December drought layer") sitting over more facets from November to the ground. If you find the slope that's a bit more open, a bit more exposed to the wind, or has received a bit more snow, suddenly the slab is thick and stiff enough to communicate a collapse, and "whumph!". The spatial variability of the Holiday slab is what leads to uncertainty. And that, plus the very weak nature of the "December drought layer" is what puts the "scary" in "scary Moderate". Also, it's worth mentioning that we continue to monitor the "freezing rain crust" that was formed on 12/28, as faceted grains are developing underneath this crust. It's distribution appears to be limited to a specific elevation range (10,500-12,000'ish) and geographic region, being found specifically around Telluride and Ophir. In snowpack tests, failures occurred beneath this crust with the overlying snow well bonded to it. Extended column tests yielded failures below the Holiday slab, but did not propagate.