Avalanche Forecast
Issued: Dec 9th, 2021 4:03PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
Conrad Janzen,
Winds will increase later on Friday as a storm makes its way into the Rockies for Saturday. Watch for slowly increasing hazard due to wind transported snow later in the day.
Summary
Weather Forecast
A NW flow will keep the temperatures cool on Friday with a warming trend and more snow expected on Saturday. Temperatures at treeline on Friday in the -10 to -15 C range and moderate winds from the NW. Some flurries expected overnight Thursday and into Friday. Saturday looks like a potentially big snowfall.
Snowpack Summary
5-20 cm of new snow over the last 36 hrs makes for 15-30 cm of soft surface snow above the Dec 2 rain crust. This crust disappears between 2100-2250 m. At treeline and above, moderate winds are developing soft slabs in immediate leeward slopes. The weak Nov 5 crust/facet interface is present near the ground.
Avalanche Summary
Ski cutting and explosive work at the local ski areas produced wind slabs from size 1-.5 on Thursday. No new natural avalanches were reported or observed but visibility was limited. The last significant skier triggered avalanche was a skier accidental size 3 triggered on Lipalian Mountain (near Lake Louise) on Sunday.
Confidence
Forecast snowfall amounts are uncertain on Saturday
Problems
Wind Slabs
Wind slabs have developed in immediate lee areas at treeline and in the alpine. These are possible to skier trigger in some areas so use caution in all steep leeward terrain at treeline and above.
- Be careful with wind loaded pockets while approaching and climbing ice routes.
- Watch for shooting cracks or stiffer feeling snow. Avoid areas that appear wind loaded.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
We continue to see occasional high consequence avalanches on the Nov 5 crust/basal facets in specific terrain features. Some slabs have initiated on this layer, while others were "step down" avalanches triggered as wind slabs or cornices hit them.
- Avoid steep convexities or areas with a thin or variable snowpack.
- Be aware of the potential for full depth avalanches due to deeply buried weak layers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 10th, 2021 4:00PM
