Avalanche Forecast
Issued: Nov 13th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Loose Dry.
Conrad Janzen,
An intense storm arrives on Sunday with forecast snow amounts ranging from 15 to 40+cm and accompanied by very strong W winds. If the larger amounts of snow arrive, the avalanche hazard will rise rapidly on Sunday and Monday.
Summary
Weather Forecast
An intense weather system arrives early Sunday morning with forecast snow amounts ranging from 15 to 40+ cm depending on the weather model and strong to extreme west winds. Another strong pulse of snow is forecast for Monday. Freezing levels will hover around 1900 m until things start to cool off on Tuesday morning.
Snowpack Summary
5-15 cm of new snow overnight with rain below 1800 m on Friday. Down 20-30 cm a thin melt-freeze crust exists in some areas that may be present up to 2500 m on solar aspects. Below this is another 10-20 cm of facetted snow over a melt-freeze crust at or near the ground. The snowpack is 40-50 cm deep at treeline with more snow in the alpine.
Avalanche Summary
Limited observations but the Lake Louise and Sunshine ski areas have reported triggering small wind slab avalanches up to size 1.5 in the alpine over the past few days. These have averaged 40 cm deep and were failing near the ground. A few more small slabs were reported into treeline elevations on Friday. No new avalanches observed on Saturday.
Confidence
Intensity of incoming weather systems is uncertain on Sunday
Problems
Wind Slabs
As the new snow and wind arrives, wind slabs will be forming rapidly over the new couple days and natural and human triggered avalanches will be very likely in steep loaded terrain. Watch for overhead hazard as cornice failures are also likely.
- Minimize overhead exposure during periods of heavy loading from new snow, wind.
- Use conservative route selection, choose moderate angled and supported terrain with low consequence.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Dry
Lots of new snow is forecast over the next couple days and large sluffs in steep alpine terrain will be almost certain if the forecast holds true.
- Be careful of loose dry sluffing in steep, confined or exposed terrain.
- Sluffs may trigger deeper instabilities.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 14th, 2021 4:00PM
