Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
Watch for wind slab development near ridgetop and in exposed terrain at upper elevations. Wind slabs will be most reactive in areas where they sit over a crust.
Keep the persistent slab problem on your mind at treeline and below.
Shooting cracks and "whumphing" are telling us that human triggering still remains possible.
Watch for wind slab development near ridgetop and in exposed terrain at upper elevations. Wind slabs will be most reactive in areas where they sit over a crust.
A layer of surface hoar (up to 40mm at tree line & below) is buried 20-60cm deep and sits on a crust. The size and reactivity of this surface hoar layer is extremely variable depending on aspect and elevation. Wind sheltered areas at lower elevations is where triggering this problem is most likely.
Field teams Monday were able to trigger steep unsupported rolls below treeline on surface hoar and a crust.
Natural avalanches up to size 1.5 were observed at valley bottom in Connaught on Sunday.
A solar triggered, natural cycle was observed earlier this week along the highway corridor with avalanches up to size 3.0
10-20 cm of recent snow with moderate to strong wind created wind slabs in the alpine and at treeline. There are a series of crusts in the upper snowpack now from solar and warming events of the last few weeks. 30-60cm beneath the surface is the Jan 26th drought layer which consists of surface hoar, facets, and a crust. This layer is widespread with largest surface hoar in sheltered areas at treeline and below.
The mid and lower snowpack is generally well settled and strong.
A high-pressure system over the region will give mostly clear skies and no precipitation.
Tonight: Cloudy with flurries. Snow: 1-2cms. Alp low -8°C. Wind SW 20-35km/h. Freezing level (FZL) 800m.
Tues: Mix of sun & cloud. Snow: 1-2cms. Wind SW 15-25 km/h. FZL 1300m
Wed: Cloudy with sunny periods. Snow: 0 cms. High -8. Wind: SW 10km/hr. FZL 1000m
Thur: Cloudy with sunny periods. Snow: 0 cms. High -7. Wind SW 15. FZL 1100m