Avalanche Forecast

Issued: Nov 29th, 2021 4:00PM

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

Avalanche Canada jleblanc, Avalanche Canada

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It's time to stay away from all avalanche terrain, as avalanches are expected to run full path to valley bottom with the arrival of this third atmospheric river.

Summary

Confidence

High - We are confident a natural avalanche cycle will begin shortly after the arrival of the incoming weather.

Weather Forecast

Another atmospheric river has begun impacting the region with heavy precipitation of snow then rain. By midday Tuesday, torrential amounts will have fallen and freezing levels will have climbed up. No relief until later Wednesday.

MONDAY NIGHT: Snow/rain 30-40 cm / Extreme, southwesterly winds / Low of 0 / Freezing level rising to 1000 m.

TUESDAY: Snow/rain; 25-35 cm / Southwesterly winds peaking at 110 km/h/ High of +3 / Freezing level rising to 1600 m.

WEDNESDAY: Snow/rain; 10-15 cm / Strong, southwesterly winds / High of -4 / Freezing level lowering to 800 m.

THURSDAY: Snow/rain; 5-10 cm / Strong, southwesterly winds / High of -8 / Freezing level around 500 m.

Avalanche Summary

Several large natural storm slabs (size 2-3) were reported in the last 24 hours in the alpine as well as some small wet snow avalanches near the rain line. With the incoming next wet warm storm, a large avalanche cycle is expected with many avalanches running full path to below treeline.

Snowpack Summary

Southern portion of region (around Terrace):

Freezing moist snowstorm can be found up to 1400 m. Above, dry snow was redistributed by strong winds on lee features at treeline and above. A prominent crust can be found near the bottom of the snowpack.

Treeline snowpack depths are estimated to be around 200-300 cm.

Northern region (around Bear Pass):

Extreme southerly winds have created thick wind slabs in the alpine. Outflows winds have also impacted the snowpack by cross-loading features at treeline and above. 

Below, two weak layers of surface hoar have been reported in sheltered areas, as well as a crust near the bottom of the snowpack.

Terrain and Travel

  • Avoid the runout zones of avalanche paths. Avalanches could run full path.
  • Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.

Problems

Storm Slabs

An icon showing Storm Slabs

Heavy snowfalls precipitation followed by intense rain will create LARGE and TOUCHY storm slabs on all aspects and elevations. It is time to stay away from avalanche terrain until the storm is over.  

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Almost Certain

Expected Size

2.5 - 3.5

Valid until: Nov 30th, 2021 4:00PM