Rising temperatures and strong sun are creating very dangerous avalanche conditions.
Avoid avalanche terrain.
Cornices are 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 70 to 120 cm deep. This layer may become reactive as temperatures peak on Wednesday.
Loose wet avalanches will become increasingly likely with rising temperatures and strong sun.
On Monday, numerous natural and artificially triggered wet loose and wind slab avalanches were observed to size 2.
Large natural persistent slab avalanches have run on buried weak layers in recent days. A size 2.5 was observed near Castle on Monday and several can be seen in this MIN from Mear Lake on Saturday.
Looking forward, we can expect to see an uptick of persistent slab avalanche activity as balmy temperatures continue to weaken the snowpack.
Surfaces are becoming moist to wet on all aspects as freezing levels climb up above the highest peaks.
Where still intact, a melt-freeze crust is found 20 to 40 cm deep, except on high-elevation north and east-facing slopes.
A persistent weak layer of surface hoar or facets from late January is buried 70 to 120 cm deep. It is most likely to be triggered on steep, rocky, convex slopes on northerly and easterly aspects at treeline and above.
Tuesday night
Clearing skies. 20 to 30 km/h southwest ridgetop winds. Treeline temperature +3 °C. Freezing level rising to 2700 m.
Wednesday
Sunny. 10 to 20 km/h south ridgetop winds. Treeline temperature +7 °C. Freezing level rising to 3000 m.
Thursday
Mostly cloudy with scattered flurries. 20 to 30 km/h southwest ridgetop winds. Treeline temperature +2 °C. Freezing level falling to 2400 m.
Friday
Mostly cloudy with scattered flurries. 10 to 20 km/h east ridgetop winds. Treeline temperature -2 °C. Freezing level 1000 to 2000 m.
More details can be found in the Mountain Weather Forecast.
