Avalanche Forecast
Issued: Nov 21st, 2012 4:49PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Wind Slabs and Deep Persistent Slabs.
brian webster,
Avalanche Canada
Summary
Weather Forecast
Heavy snow fall warning for Banff and Lake Louise tonight. Some forecasts say 10-15 at valley bottom locations. Can expect double this amount in the alpine. Temperatures will get colder towards the end of the week.
Snowpack Summary
30 cm of settled storm snow at tree-line along the continental divide along with moderate to strong westerly winds has created wind-slabs in the alpine. Easy shears at storm snow interface and mod shears down 60 cm on Nov 6 crust.
Avalanche Summary
No natural avalanches were observed throughout the forecast area today. Several naturals were reported yesterday from the Icefields Parkway. Sunshine Ski Hill reported up to Class 2.5 slabs with explosives running in the storm snow.
Confidence
Problems
Storm Slabs
Heavy snowfall forecasted for night of Nov 21. Expect 10-15 cm at valley bottom with double that amount in the alpine. This new snow will increase the avalanche hazard for Thursday.
- The new snow will requires several days to settle and stabilize.
- Choose conservative lines and watch for clues of instability.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
Recent new snow and winds have produced wind slabs on lee aspects in the alpine. These slabs are reactive to skier triggering in specific locations.
Aspects: North, North East, East, South East.
Elevations: Alpine.
Likelihood
Expected Size
Deep Persistent Slabs
Although no recent natural avalanches have been observed on this layer, this still is a significant interface to be aware of. Latest storm inputs may be enough to overload this layer.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 22nd, 2012 4:00PM
