Avalanche Forecast

Issued: Dec 20th, 2020 8:04AM

The alpine rating is high, the treeline rating is high, and the below treeline rating is high. Known problems include Storm Slabs and Persistent Slabs.

Kate Ryan,

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.

Summary

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

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

Valid until: Dec 21st, 2020 8:00AM