Avalanche Forecast
Issued: Feb 21st, 2020 4:00PM
The alpine rating is Wind Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeNew wind slabs are likely forming up high. Use added caution on steep slopes in open trees as a slab of snow may rest on surface hoar, particularly in the eastern part of the region.
Summary
Confidence
High -
Weather Forecast
FRIDAY NIGHT: Increasing clouds, moderate to strong southwest wind, alpine temperature -5 C.
SATURDAY: Mix of sun and cloud with isolated flurries, accumulation 1 to 3 cm, moderate west wind, alpine temperature -5 C, freezing level 1300 m.
SUNDAY: Cloudy with snowfall, accumulation 5 to 10 cm, moderate southwest wind, alpine temperature -6 C, freezing level 900 m.
MONDAY: Morning snowfall and afternoon clearing, accumulation 2 to 5 cm, light to moderate northwest wind, alpine temperature -7 C, freezing level 1000 m.
Avalanche Summary
A few slab avalanches were triggered by skiers on Thursday. They were both on northerly aspects. One of them was a wind loaded feature and the other was suspected to have failed on the weak layer described in the snowpack summary, with a slab depth of about 30 cm.
Snowpack Summary
A dusting of snow is forecast for Saturday, along with strong southwest wind. New wind slabs are likely to form in lee terrain features. The new snow will accumulate onto a widespread layer of feathery surface hoar crystals or a melt-freeze crust on southerly aspects.
A 20 to 30 cm thick slab has been reactive to human traffic since last weekend, where the snow overlies a weak layer of surface hoar. The slab has been most reactive in open trees in the eastern part of the region.
The remainder of the snowpack is well-settled.
Terrain and Travel
- Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Problems
Wind Slabs
Strong southwest wind and a dusting of new snow will form new wind slabs in lee terrain features near ridges.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A 20 to 30 cm slab has been reactive to riders in the past week. The slab has been touchiest in open trees in the east of the region, where the slab rests on a layer of weak and feathery surface hoar crystals. The spatial distribution of the surface hoar layer is unclear and may be spottier in the west of the region.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 22nd, 2020 5:00PM