Avalanche Forecast

Good

A series of Pacific frontal systems will continue to dominate the weather pattern and hit the coastal regions throughout the forecast period. At this point model runs seem to be in agreement with timing and precipitation amounts.Saturday/Saturday night: Snow amounts 5-10 cm during the day with near 25 cm overnight. Alpine temperatures high of -3.0. Light-moderate SE ridgetop winds and freezing levels rising to 1000 m. Sunday: Snow amounts near 20 cm. Alpine temperatures near -7.0. Moderate-strong SW ridgetop winds and freezing levels at valley bottom.Monday: Light snow amounts and unsettled conditions expected as the bulk of the system moves inland.

On Thursday numerous slab avalanches up to size 2.5 were triggered with explosives control and remote triggering was reported form a distance of 15 m, which indicates the continued sensitivity nature of the avalanche problem.. Natural and human-triggered storm slabs to size 2.5 were observed on Tuesday and Wednesday.

Between 60 and 100cm of recent snowfall overlies a variety of old snow surfaces which were buried on February 10th. These old surfaces consist of weak surface facets, surface hoar (more predominant at treeline and below treeline elevations), a scoured crust, wind press, or any combination of these. Professionals are expressing particular concern for the combination of buried facets on a crust being unusually reactive at treeline and below. Reports of whumphing and widespread avalanche activity further indicate a poor bond between the new snow and these old surfaces. Strong to extreme winds are shifting the new snow into deeper, reactive wind slabs in exposed terrain.The mid and lower snowpack are generally strong and well-settled. Basal facets and depth hoar are likely to exist in some parts of the region, but triggering has become unlikely.