Avalanche Forecast

Issued: Dec 27th, 2019 4:30PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Storm Slabs.

Avalanche Canada astclair, Avalanche Canada

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The recent 15-20 cm of new snow is not expected to bond well to previous snow surfaces, and it may form slabs that are possible to trigger in deeper areas at higher elevations or where the snow has been drifted by wind.

Summary

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

Friday night: Mostly cloudy, light to moderate northwest winds, temperatures around -3 C.

Saturday: Mostly cloudy with scattered wet flurries and 1-3 cm of accumulation overnight. Moderate to strong southwest winds. Alpine high temperatures near 0 C with freezing levels to 1000 meters, rising to 1200 meters overnight.

Sunday: Decreasing cloud with scattered wet flurries and a trace to 3 cm of accumulation. Light southeast winds. Alpine high temperatures around 2 C with freezing levels to 1500 meters.

Monday: Increasing cloud, light to moderate west winds, alpine high temperatures around 2 C with freezing levels rising to 2000 meters.

Avalanche Summary

No new avalanches have been reported in the region since the widespread natural avalanche cycle brought on by last weekend's storm.

The recent snow presents a new storm slab problem to manage on Saturday. Thicker, more reactive slabs should be expected at higher, more wind-exposed elevations.

Snowpack Summary

15-20 cm of new snow from the last 24 hours fell on a mix of crusts or old snow surfaces that are not likely to bond well. In areas where snow accumulations are deeper, this new layer may form a cohesive slab with the potential to slide.

Below the new storm snow, 50-100 cm of snow from last weekend comprises the upper snowpack above 1200 meters. This storm snow is well settled with a strong bond to the previous surface. Below 1200 meters, the snowpack diminishes rapidly with elevation.

Terrain and Travel

  • Be alert to conditions that change with elevation.
  • Carefully monitor the bond between the new snow and old surface.
  • Use small low consequence slopes to test the bond of the new snow.
  • Dial back your terrain choices if you are seeing more than 20 cm of new snow.

Problems

Storm Slabs

An icon showing Storm Slabs

15-20 cm of new snow presents a storm slab problem to manage on Saturday, as the latest snow is not expected to bond well with the pre-existing snow surfaces. Thicker, more reactive slabs are expected to form in wind-exposed areas or at higher elevations.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 28th, 2019 5:00PM