Avalanche Forecast

Issued: Dec 20th, 2019 4:00PM

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.

Avalanche Canada kdevine, Avalanche Canada

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It's a great weekend to hit the ski hill! Widespread avalanche activity is expected today. Avoid avalanche terrain.

Summary

Confidence

High -

Weather Forecast

FRIDAY NIGHT - Periods of snow, 15-25 cm / southwest wind, 30-60 km/h / alpine low temperature near -3 / freezing level 1500 m

SATURDAY - Periods of snow, 15-30 cm / southwest wind, 40-80 km/h / alpine high temperature near -3 / freezing level 1500 m

SUNDAY - Cloudy with sunny periods and isolated flurries, up to 5 cm / southwest wind, 10-20 km/h / alpine high temperature near -5 / freezing level 1000 m

MONDAY - A mix of sun and cloud / southwest wind, 10-20 km/h / alpine high temperature near -7

Avalanche Summary

Significant snowfall amounts, warm temperatures and strong to extreme winds will mean that a natural avalanche cycle is expected on Saturday.

On Friday there were reports of numerous natural, human and explosives triggered avalanches. 

Snowpack Summary

The storm rages on in the Purcells with 15-25 overnight on Friday and another 15-30 cm expected during the day on Saturday. By the end of the day on Saturday, this will make for a total of 50-95 cm of snow in 48 hours. Storm slabs are expected to be widespread and very reactive.

Anywhere from 70-150 cm of recent snow may sit on a weak layer of surface hoar in sheltered areas at treeline. A second layer of surface hoar primarily found in the in north of the region is found 90-170 cm below the surface in sheltered areas at treeline. There are a variety of crusts buried in the mid to lower snowpack. These crusts have mostly broken down. The base of the snowpack generally consists of facets and depth hoar.

Terrain and Travel

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

Problems

Storm Slabs

An icon showing Storm Slabs

Continued intense loading from heavy snow and strong winds will mean that an avalanche cycle is almost certain. Avoid avalanche terrain, and don't underestimate the potential for avalanches to run full path.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1.5 - 3

Persistent Slabs

An icon showing Persistent Slabs

Weak layers near the base of the snowpack remain a concern. Likely trigger points are shallow rocky areas. 

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Dec 21st, 2019 5:00PM

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