Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 1–2
Strong northerly winds will be transporting snow into reactive wind slabs in all exposed terrain especially near ridge crests and sharp breaks in terrain.
Be suspicious of areas where the wind is actively depositing snow.
Strong wind can make windslabs in less common areas, like part way down large slopes, and on steep cut banks.
Strong northerly winds will be transporting snow into reactive wind slabs in all exposed terrain especially near ridge crests and sharp breaks in terrain.
A weak layer of surface hoar and/or facets buried ~100 cm deep has produced occasional large, widely propagating avalanches on north to east aspects above 1500 m. Some avalanches have been remotely triggered from hundreds of meters away! A layer at this depth may not show obvious signs of instability. Best to avoid steep or unsupported high consequence alpine terrain.
A natural avalanche cycle up to size 3 has been observed from the highway in the inland areas around Paddy peak. We suspect that some of these may include step-downs to buried weak layers.
On Friday, our field team also observed new windslab avalanches up to size 2 and loose snow sluffing from steep alpine terrain around the White Pass.
Recent snow has been stiffened at the surface in exposed areas and transported into wind slabs by strong outflow wind at all exposed elevations.
The mid snowpack is generally hard with a couple of crusts buried 60+ cm and 100+ cm deep, these have been problematic on north to east aspects as high as 1700 m, where they are covered in an overlying layer of weak surface hoar crystals. In inland areas these weak layers are closer to the surface and are easier to trigger.
At the base of the snowpack large sugary crystals persist.
Saturday night
Possible flurries. Moderate to strong northeasterly wind. -20 ºC.
Sunday
Sunny. Moderate to strong northeasterly wind. Alpine temperature -16 ºC.
Monday
Mostly cloudy. Snow beginning in the afternoon, up to 5 cm. Strong northerly wind. Inversion, alpine high -10 ºC.
Tuesday
Mostly sunny. Strong northerly outflow wind. Alpine high -15 ºC.
More details can be found in the Mountain Weather Forecast.