Avalanche Forecast
Issued: Nov 18th, 2019 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
aaron beardmore,
Parks Canada
Heavy loads (explosives) producing size 2 avalanches on the October crust. Keep on the look out for wind-slabs at your local level.
Summary
Weather Forecast
Light precip (7-10cm) followed by a cooling trend is expected Tuesday. Winds will also abate, however wind velocity will rise and fall from the moderate range to calm over the next few days. Clearing expected early Thursday.
Snowpack Summary
Yesterday, 5-10 cm of new snow with warm temps and strong SW winds was loaded in lee areas and built cornices. 10-25 cm of settled snow sits over the Nov 8 crust. Faceting observed near the ground and Oct crust, resulting in easy test results in some areas. Treeline snow depths range from 50-80 cm, with up to 110 cm in wind loaded alpine areas.
Avalanche Summary
Lake Louise ski area was reporting that explosive control was producing wind-slabs that would step down to the Oct crust producing numerous size 2 avalanches.
Confidence
Wind effect is extremely variable on Monday
Problems
Wind Slabs
Small amounts of new snow and recent strong SW wind on Monday have created new wind-slabs in lee areas in the alpine. The wind was strong enough to move snow around at treeline but slab development was less prominent at this elevation band.
- If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
The basal facets and Oct crust have been most reactive in the Lake Louise area, but it is likely that similar pockets exist throughout the forecast area. Keep watching for weak areas at the base of the snowpack, especially in steep or convex terrain.
- Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.
- Convex features and steep unsupported slopes will be most prone to triggering.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 19th, 2019 4:00PM
