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Avalanche Forecast

Dec 12th, 2019–Dec 13th, 2019
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Sea To Sky.

Although the storm has eased off, storm slabs are still likely to be encountered and could be reactive to human triggering, especially in wind loaded areas.

Confidence

Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.

Weather Forecast

THURSDAY NIGHT - Flurries, 5 cm / southwest winds, 20-30 km/h / alpine low temperature near -6 / freezing level 1000 m

FRIDAY - Mainly cloudy with isolated flurries / southwest winds 20-30 km/h / alpine high temperature near -6 / freezing level 1000 m

SATURDAY - Cloudy with sunny periods / light southwest winds / alpine high temperature near -7

SUNDAY - A mix of sun and cloud / light northwest winds / alpine high temperature near -8

Avalanche Summary

On Thursday, there were several reports of human and explosives triggered avalanches up to size 2. Some of these avalanches stepped down to a weak crust/facet layer that was buried in mid November.

No new avalanches were reported on Wednesday.

Snowpack Summary

15-25 cm of new snow likely sits on a weak layer of feathery surface hoar in many areas, as well as sugary faceted snow in some areas. There is a crust from mid November that is now down approximately 45-100 cm. Recent snowpack tests have shown that the snow above the crust is weak and could produce avalanches. The snowpack is unusually shallow and weak for the Sea to Sky region. Snowpack depths range between 80-200 cm and taper quickly at lower elevations.

Avalanche Problems

Storm Slabs

Fresh storm slabs are likely sitting on a weak layer of surface hoar and/or facets. These slabs may be reactive to human triggers, especially in wind loaded areas. The potential exists for storm slabs to step down to a weak layer buried in mid November.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2