Avalanche Forecast

Moderate - Due to the number of field observations

FRIDAY NIGHT: Brief clearing overnight, light to moderate wind out of the west, alpine temperatures drop to -12 C.SATURDAY: Snow starting late in the day with 10 cm overnight, strong wind from the south increasing throughout the day, alpine high temperatures around -7 C.SUNDAY: Another 10 cm of snow throughout the day, strong wind out of the south, alpine high temperatures around -3 C.MONDAY: Mainly cloudy with isolated flurries, strong wind out of the south, alpine high temperatures around -3 C.

Several natural slab avalanches were reported during the stormy weather over the past few days. Two large (size 2) avalanches were observed on east-facing wind-loaded slopes near treeline (1700 m) and several smaller slabs have been reported in steep gullies at lower elevations. See this MIN report. Sparse reports and poor visibility have likely limited observation of larger avalanches in the alpine. These avalanches are likely running on the interface between the storm snow and old snow roughly 20-50 cm below the surface. This slab has produced notable cracking with skier traffic and could produce large human triggered avalanches on steeper slopes.

20-30 cm of new snow has covered the region so far this week, the product of an ongoing series of storms. Areas like Howsons in the far southwest had storm totals closer to 50 cm. The combination of new snow and forecast strong south winds is likely forming thicker and more sensitive wind deposits at higher elevations. Even below the wind, the new snow will need a bit more time to form a good bond with the weak surface hoar and facets that were sitting on the surface prior to the storms. (see this MIN report).A hard crust was reported 10-20 cm below the previous snow surface (so now closer to 30-50 cm deep) and in some locations there is an early season crust with facets near the bottom of the snowpack. The new snow has brought alpine snow depths up to 100-150 cm and started to cover the rocks, stumps, and open creeks at lower elevations.