Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
A crust with weak crystals overtop is buried 20 to 30 cm. This problem is specific to areas where a cohesive slab has formed over the layer, such as wind-loaded features.
Increasing winds will impact loose snow. Check for wind-loaded pockets around ridgecrests and steep rolls.
A crust with weak crystals overtop is buried 20 to 30 cm. This problem is specific to areas where a cohesive slab has formed over the layer, such as wind-loaded features.
On Wednesday this MIN post reported whumpfing and shooting cracks west of White Pass.
On Tuesday, our field team noted a natural size 2 slab avalanche on a north aspect at 1300m. (See photo below). The slab was 20-30 cm deep and failed on facets above a crust, the weak layer described in the snowpack summary.
Reports have been limited, if you head out in the mountains, please consider sharing your observations on the Mountain Information Network.
Recent outflow winds have scoured windward faces in the alpine and loaded lee slopes. Up to 20 cm of soft snow can be found in sheltered areas.
The primary layer of concern is weak facets and in some cases surface hoar, overlying a crust. The interface is now buried 20 to 30 cm deep and extends up to 1750 m.
Despite the presence of faceted grains in the lower snowpack, there are no current layers of concern below the crust.
Snowpack depths range from about 70 to 180 cm.
Saturday night
Cloudy. 20 to 30 km/h south ridgetop wind. Treeline temperature -25 °C.
Sunday
Cloudy with isolated flurries, trace to 5 cm. 30, gusting to 60 km/h ridgetop southwest wind. Treeline temperature -16°C.
Monday
Cloudy with isolated flurries, 5 cm. 40 to 80 km/h ridgetop south wind. Treeline temperature -10°C.
Tuesday
Cloudy with isolated flurries, 5 cm. 40 to 80 km/h ridgetop south wind. Treeline temperature -10°C.
More details can be found in the Mountain Weather Forecast.