Avalanche Forecast
Issued: Jan 22nd, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Deep Persistent Slabs.
Mark Herbison,
There is a special avalanche warning in effect for our area.
Rising freezing levels and solar radiation may trigger another large avalanche cycle this weekend.
Minimize your exposure to overhead avalanche terrain.
Summary
Weather Forecast
Battle of the Weather Models continue, as they can't seem to agree on freezing levels. Sunday will see a mix of sun and cloud with a freezing level up to 2300m (highest forecasted elevation) and an alpine high of -2. Winds will be from the West, 25-60km/hr. Freezing level will drop back down to valley bottom on Monday. No new snow in the forecast.
Snowpack Summary
Up to 35cm of recent snow now buries the Jan 20th (2-4mm) surface hoar. The Jan 11 (2-5mm) surface hoar is down ~70-90cm. The Dec 1 crust/facet combo is down ~1.5 - 2.5m. This layer came alive last storm and will be a lingering concern. Wind and warming temps will promote the formation of wind slabs along ridge lines and cross loaded features.
Avalanche Summary
Helicopter Avalanche Control on Saturday, just West of the Park produced several size 4 avalanches.
A natural avalanche cycle occurred on Thursday with a notable size 4 off of Ross Peak that ran into the Elephants Trunk in Loop Brook.
A widespread natural and artillery avalanche cycle occurred last Monday up to size 4, with some crowns over 2m deep.
Confidence
Intensity of incoming weather systems is uncertain on Sunday
Problems
Wind Slabs
Up to 35cm of new snow, combined with warm temps and strong gusty winds are building fresh wind slab. These may bury surface hoar or a preserved stellar layer and may be sensitive to human triggering.
- Convex features and steep unsupported slopes will be most prone to triggering.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
This layer has been recently active and in some instances has been enough to step down to the deeper Dec 1 curst/facet layer. Investigate the snowpack before committing to your line.
- Be wary of slopes that did not previously avalanche
- If triggered the persistent slabs may step down to deeper layers resulting in very large avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
The Dec 1 crust/facet layer woke up last Monday, resulting in numerous very large avalanches This is now a low probability / high consequence avalanche problem. It will be stubborn to trigger, but if it goes the results will be very large.
- Avoid thin, rocky or unsupported slopes.
- Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 23rd, 2022 4:00PM
