Confidence
Fair - Timing, track, or intensity of incoming weather is uncertain
Weather Forecast
Cold dry air moving down from the Arctic begins to take hold of the region Sunday afternoon. Winds switch to the N, NE as this air mass moves in & temperatures drop. A daytime high of -10 & an overnight low of -18 is forecast for Sunday. The mercury drops a little further Monday; H: -12, L: -30. This pattern will likely persist through Tuesday evening. No significant precipitation is expected for the next 72 hours.
Avalanche Summary
No new avalanches to report from the last 24 hours.
Snowpack Summary
Strong southwest winds created windslabs in the alpine and at treeline last week. I would suspect that these wind slabs have since gained some strength. 10 - 20 cm fell in the region Friday night with very little wind. A rain crust exists below 1500m. The mid-pack is reported to be strong, and I have not heard anyone talk about early season layers deep in the snowpack. That being said, there is still a lot of variation due to the strong winds that have accompanied most storms this winter in the region. I would continue to be suspect of thin snowpack areas. Winds increase Sunday switching to the N forming fresh sensitive windslabs.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.