We have some uncertainty about the likelihood of persistent slabs. In times of uncertainty, conservative terrain choices are the best defense. Seek out low-consequence terrain.
Wind slabs could still linger in the alpine. If triggered, wind slabs may step down to deeper layers, causing larger avalanches.
A layer of facets over a crust is buried 80 to 150cm, and has recently produced very large avalanches. It appears to be most reactive in areas closer to the coast.
Last Saturday, a skier-triggered size 2 persistent slab was reported on the US side of the border. This avalanche occurred on a northwest aspect at approximately 1500 m and ran on the mid-February layer. This layer is a concern in our region as well.
We suspect that avalanche activity has been tapering off over the past few days, but observations have been limited. If you are heading into the mountains, please consider filling out a Mountain Information Network report.
At ridgelines and in exposed terrain, strong winds have formed slabs and hard wind-pressed surfaces. Softer snow may still be found in sheltered areas or faceting northerly aspects. A sun crust may be present on or near the surface on sun-exposed slopes.
A persistent weak layer of facets and crust is buried 80 to 150 cm deep, extending up to about 1400 m. The greatest concern for triggering comes from large loads, such as cornice falls, or from human triggering in areas where the snowpack transitions from thin to thick. This layer appears most reactive closer to the coast, with decreasing reactivity further inland.
Thursday Night
Mostly clear skies. 20 km/h southeast ridgetop wind. Treeline temperature -7 °C.
Friday
Mostly cloudy. 20 km/h southeast ridgetop wind. Treeline temperature -7 °C.
Saturday
Mostly cloudy. 2 to 3 cm of snow. 30 km/h south ridgetop wind. Treeline temperature -5 °C.
Sunday
Mostly cloudy. 4 to 5 cm of snow. 30 km/h southeast ridgetop wind. Treeline temperature -4 °C.
More details can be found in the Mountain Weather Forecast.
