Southern San Juan
SnowpackChris Bilbrey · Mar 1, 2024 · Southern San Juan
Weather
Cool, crisp morning. Moderate winds helped pump the brakes on today's warm up under mostly sunny skies.
Snowpack
The denser make-up of the recent storm snow appears to have limited wet snow activity from warm, sunny weather over the last couple of days. Only rollerball/ pinwheel action from rocky areas, and none entrained additional snow while traveling downhill. Now that sunny slopes have a robust surface crust, this will likely reduce surface warming in the coming days without calmer, warmer conditions. Faceting of the storm snow has already begun under the new crusts, and will be something to monitor if we see meaningful snowfall over the next few days. We dug on an east and north-facing slope below treeline to see how the last storm load is influencing sensitivity of upper faceted layers. On both aspects, we observed moderate sudden collapse failures within the new snow, failing at two thick layers of graupel. In our east pit, we observed moderate, sudden collapse failures in 4F facets below a 2-inch crust. Failures were dirty and this interface likely needs a moderate snow load to be a concern. However, boot penetration was through the crust and suggest a quick warm-up could help weaken the buried crust and increase potential failure. In our north pit, we observed moderate resistant planar failures in 1F- facets. Failures were clean and planar. Boot penetration on shady slopes was around 30 cm, and ski penetration was 10 cm or less. Both persistent weak layers we evaluated were around 10 cm thick. No cracking or collapsing on our travels.