Rising temperatures and strong sun are creating very dangerous avalanche conditions. Natural avalanches are likely. Avoid avalanche terrain.
Cornices are large, looming and becoming weak with warm temperatures and sun. A large cornice fall can be dangerous on its own, and can also trigger deep slabs on slopes below.
A persistent weak layer of surface hoar or facets is buried 100 to 180 cm deep. This layer may become reactive as temperatures peak on Wednesday.
As temperatures rise, expect a heavy, wet upper snowpack to produce slab and loose wet avalanches, especially on sun-exposed slopes.
Numerous natural and artificially triggered size 1 to 2.5 storm slab avalanches were reported on Monday.
Looking forward, we can expect this activity to continue as temperatures continue to climb, with the possibility of deeper avalanches running on buried weak layers.
The upper snowpack is heavy and moist or wet at all elevations.
Where still intact, a crust is buried 30 to 100 cm deep, except on high-elevation north and east-facing slopes.
A surface hoar or facet layer from late January is buried 100 to 180 cm deep on north and east aspects at treeline and above. Although it been observed to be improving, we won't rule it out as a failure plane as balmy temperatures warm and weaken the snowpack on Wednesday.
Tuesday night
Clearing skies. 20 to 30 km/h southwest ridgetop winds. Treeline temperature +5 °C. Freezing level rising to 2700 m.
Wednesday
Sunny. 10 to 20 km/h south ridgetop winds. Treeline temperature +10 °C. Freezing level rising to 3000 m.
Thursday
Flurries bringing 1 to 5 cm of snow. 30 to 40 km/h southwest ridgetop winds. Treeline temperature +1 °C. Freezing level 2500 to 2300 m.
Friday
Flurries bringing 1 to 5 cm of snow. 10 to 20 km/h northwest ridgetop winds. Treeline temperature -1 °C. Freezing level 1000 to 2000 m.
More details can be found in the Mountain Weather Forecast.
