Avalanche Forecast
Issued: Feb 20th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Cornices.
ahanna,
Avalanche Canada
Another bright sunny day in the Lizard/Flathead ranges! As you get out there to enjoy this fantastic weather, remember to avoid overhead cornice hazard, watch for fresh wind slabs and keep an eye on steep south aspects for signs of solar warming.
Summary
Confidence
High -
Weather Forecast
Thursday night: Clear. Moderate to strong southwest wind. Freezing level valley bottom.
Friday: Sunny. Moderate to strong southwest wind. Freezing level 1500 m.
Saturday: Mix of sun and cloud. Moderate west wind easing. Freezing level 1500 m.
Sunday: Mix of sun and cloud. Light to moderate southwest wind. Freezing level 1200 m.
Avalanche Summary
No new avalanche activity reported Wednesday. Explosive control work Monday and Tuesday produced mostly size 2 cornices, some triggering thin slabs on slopes below.
There have been two reports of avalanches running on the early February rain crust. Explosive control work produced a size 2 with crown depth up to 80 cm on Tuesday. A skier triggered size 2 on a southeast aspect is described in this MIN report from Sunday.
Snowpack Summary
A thin sun crust may be found at the surface on steep solar aspects. Variable wind affect in the alpine and near treeline with soft slabs in immediate lees.
A thick rain crust sits 30-60 cm below the surface, up to 2100 m. Recent avalanche activity has been observed at the faceting interface between this crust and overlying snow.
The bottom 20 cm of the snowpack consists of basal facets and decomposing crusts that have not been an active avalanche problem since December, but could reemerge as a problem after sustained warming.
Terrain and Travel
- Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet
- Avoid exposure to slopes that have cornices overhead.
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
- Keep in mind the crust offers an excellent bed surface for avalanches.
Problems
Wind Slabs
Wind transport continues to build wind slabs and cornices in the alpine. Fresh deposits will be most reactive to human triggers. Below 2100 m, wind slabs up to 80 cm thick sit on a thick melt freeze crust which could serve as an excellent bed surface.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Natural cornice falls have been reported recently and will likely continue as the wind and sun continue over the next few days. Cornice falls are dangerous in their own right but they may also trigger avalanches on slopes they impact.
Aspects: North, North East, East.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Feb 21st, 2020 5:00PM
