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Archived

Avalanche Forecast

Dec 20th, 2020–Dec 21st, 2020
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
4: High
The avalanche danger rating at treeline will be high
Below Treeline
4: High
The avalanche danger rating below treeline will be high
Alpine
5: Extreme
The avalanche danger rating in the alpine will be extreme
Treeline
5: Extreme
The avalanche danger rating at treeline will be extreme
Below Treeline
4: High
The avalanche danger rating below treeline will be high
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable

Regions: Glacier.

Spicy avalanche conditions on all aspects and elevations!

Now is the time to avoid backcountry avalanche terrain and enjoy some laps at your local ski hill.

Weather Forecast

The weather system over southern BC will exit the province this morning, with the next system poised to arrive early tomorrow.

Today: Cloudy with sunny periods and isolated flurries. Freezing level 1200m. Moderate gusting extreme W wind.

Tonight: Snow (16 cm). Low -9 C. Moderate W wind.

Monday: Snow (14 cm). High -9 C. Light NE wind.

Snowpack Summary

26+ cm of new snow brings the 4 day storm total to over 1 meter! Strong S-SW winds and warm temps continue to build a sensitive slab at all elevations. The Dec 13 surface hoar/facets are down 90cm+ and the Dec 7 crust/surface hoar layer is down 100cm+. The Nov 5 crust lingers near the base of the snowpack but has been unreactive recently.

Avalanche Summary

A widespread natural avalanche cycle began overnight and continues this morning.

A widespread cycle of natural and artillery controlled avalanches up to size 3.5 occurred in the highway corridor (and likely in the backcountry) yesterday.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Avalanche Problems

Storm Slabs

Last nights heavy snowfall, strong S-SW winds and warm temps are the perfect recipe for building fresh reactive storm slabs.

  • If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Very Likely

Expected Size: 1.5 - 3

Persistent Slabs

1m+ sits on persistent layers of rain crust/ surface hoar/ or suncrust. Triggered storm slabs have the potential to step down to these interfaces, triggering very large avalanches.

  • Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.
  • Be aware of the potential for wide propagations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 2 - 4