Avalanche Forecast
Issued: Dec 20th, 2019 5:00PM
The alpine rating is Wind Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeRecent snow and wind has promoted wind slab development at upper elevations.
Summary
Confidence
Low - Uncertainty is due to the limited number of field observations.
Weather Forecast
Friday Night: Cloudy with scattered flurries. Alpine temperature -5 C. South wind 20-40 km/hr.
Saturday: Cloudy with sunny periods. Alpine temperature -7 C. Southwest wind 15-20 km/hr.
Sunday: Mix of sun and cloud. Alpine temperature -7 C. Southwest wind 10-20 km/hr.
Monday: Cloudy with isolated flurries. Alpine temperature -8 C. south wind 20-30 km/hr.Â
Avalanche Summary
There have been no recent reports of avalanche activity.
Between Tuesday and Wednesday, and further east of the Northwest Inland region, a natural wind slab avalanche cycle to size 2.5 in alpine and treeline areas was triggered by intense wind loading.
Snowpack Summary
15-30 cm of snow fell in the region early this week. Strong south-southwesterly winds have since developed reactive wind slabs, especially around ridge features and into the alpine.Â
Reports suggest there are 2 buried layers of surface hoar in the upper snowpack - one down 15-25 cm below the new snow, and another down 25-40. Where wind has scoured the snowpack, a crust from November is at or near the surface. In leeward terrain, a this crust is 40-60 cm deep, and may include surface hoar in sheltered openings up to treeline.
Older crusts can be found deeper in the snowpack and are generally breaking down. In areas with a relatively thin snowpack, the base of the snowpack likely consists of weak faceted grains.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Wind Slabs
Recent new snow has been redistributed by wind blowing from a variety of directions.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 21st, 2019 5:00PM