Avalanche Forecast

FRIDAY NIGHT: Cloudy with starry breaks and isolated flurries, trace accumulation, light east wind, treeline temperatures warm to -6 C.

SATURDAY: Sunny, light wind from the northeast, freezing level rising to 1500 m, treeline temperatures warm to -3 C.

SUNDAY: Mostly sunny, increasing southwest wind, treeline temperatures warm to -2 C.

MONDAY: Mix of sun and cloud, increasing southeast wind, freezing level rising above 1600 m, treeline temperatures above freezing.

Avalanche activity the last week has primarily been large cornice failures on north and east facing slopes. For the most part these have not triggered avalanches on the slopes below, with the exception of one very large (size 4) persistent slab avalanche on Monday that was triggered by a massive cornice failure on a northeast aspect in the Selkirks. The triggering of this avalanche was only possible with an extremely large load and is not representative of the general conditions of the region as a whole.

A small human-triggered wind slab avalanche (size 1) was reported in Glacier National Park on Wednesday morning, which is indicative of the lingering possibility of small wind slab avalanches in isolated terrain.

At treeline and above up to 20 cm of consolidated, wind-affected snow covers a crust all aspects up to 2200 m and mountain tops on solar aspects. Recent northeast wind has formed wind slabs on lee aspects below ridgetops and left a variety of wind affected surfaces. Another prominent crust layer is found 30-70 cm deep. 

Cornices are very large and exposure to slopes beneath them should be minimized, especially if the weather is sunny, warm, or windy.

• Pay attention to cornices and give them a wide berth when traveling on or below ridges.
• Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
• Back off slopes as the surface becomes moist or wet with rising temperatures.