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Avalanche Forecast

Dec 21st, 2019–Dec 22nd, 2019
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
3: Considerable
The avalanche danger rating in the alpine will be considerable
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
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
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: Purcells.

The Purcells have been getting blasted by this storm and with another round of fresh snow on Saturday night, avalanche hazard remains elevated. Continue to avoid avalanche terrain.

Confidence

Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

SATURDAY NIGHT - Periods of snow, 10-20 cm / southwest wind, 20-40 km/h / alpine low temperature near -8

SUNDAY - Mainly cloudy with flurries, up to 5 cm / southwest wind, 10-20 km/h / alpine high temperature near -7

MONDAY - Mainly cloudy with scattered flurries, 5 cm / southwest wind, 10-20 km/h / alpine high temperature near -7

TUESDAY - Cloudy with sunny periods / southwest wind, 10-20 km/h / alpine high temperature near -10

Avalanche Summary

With more snow overnight on Saturday, avalanche activity is expected to continue to be widespread on Sunday.

Avalanche activity was widespread on Saturday with reports of natural, human and explosives triggered avalanches up to size 3.

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

Snowpack Summary

The storm delivers a final punch to the Purcells with another 10-20 cm overnight Saturday, and up to 5 cm during the day on Sunday. The region has received a whopping 60-115 cm of new snow since Thursday night. Storm slabs are widespread and are expected to continue to be reactive on Sunday.

Anywhere from 70-160 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 90-180 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.

Avalanche Problems

Storm Slabs

Avalanche activity is expected to be widespread. 

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1.5 - 3

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

Expected Size: 2 - 3