Avalanche Forecast

Issued: Nov 25th, 2019 4:00PM

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

Avalanche Canada shorton, Avalanche Canada

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Cold windy weather this week will make avalanches most likely in wind affected terrain at higher elevations.

Summary

Confidence

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

Weather Forecast

MONDAY NIGHT: Partly cloudy with some isolated flurries, 30 km/h wind from the northwest, alpine temperatures drop to -12 C.

TUESDAY: Increasing cloud throughout the day with isolated flurries bringing trace amounts of snow, light wind, alpine temperatures around -12 C.

WEDNESDAY: Cloudy with isolated flurries bringing trace amounts of snow, 40-60 km/h wind from the northeast, alpine temperatures around -14 C.

THURSDAY: Cloudy in the morning and clearing in the afternoon, 30-50 km/h wind from the northeast, alpine temperatures around -16 C.

Avalanche Summary

The most likely place for avalanches right now is on slopes where the wind has blown the recent snow into wind slabs. A recent MIN report shows the type of terrain where triggering thin wind slabs is a concern. This group of skiers reported a 20 cm thick slab that was triggered on north-facing slope at 2100 m. Observations are limited this time of year, so there is a fair bit of uncertainty about the extent of current avalanche activity.

Snowpack Summary

Winter weather has arrived, but the snowpack is still shallow with lots or rocks and logs poking out (see photos from these recent MIN reports here and here). The snowpack is 80 to 100 cm deep on north-facing alpine terrain, while south-facing terrain only has 30 to 80 cm of snow. 

5-20 cm of low density snow on the surface sits above a widespread crusts. A few layers have been observed in the lower snowpack including some crusts and layer of surface hoar 50 cm below the surface (see video here). At the present time these layers are unlikely to produce avalanches, but we are monitoring them as they could develop into problems in the future. 

Problems

Wind Slabs

An icon showing Wind Slabs

The most likely spot for avalanches is at higher elevations where wind has blown the snow into wind slabs. Be careful around ridgetops and alpine terrain where these wind slabs may exist.

Aspects: North, North East, East, South East, South.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 1.5

Valid until: Nov 26th, 2019 4:00PM

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