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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Wind slab avalanches are possible to trigger near ridgetops and in alpine terrain.

Summary

Confidence

Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack. Uncertainty is due to the limited number of field observations.

Weather Forecast

MONDAY NIGHT: Increasing cloud with a few isolated flurries, 20 km/h wind from the northwest, freezing level dropping to valley bottom, alpine temperatures dropping to -12 C.

TUESDAY: Cloudy with isolated flurries, 5-10 cm of snow near the Alberta border and less in the Lizard Range, 30 km/h wind from the southeast, alpine temperatures around -12 C.

WEDNESDAY: Flurries with 10-20 cm of snow near the Alberta border and 5-10 cm around the Lizard Range, 50-80 km/h wind from the northeast, alpine temperatures around -16 C.

THURSDAY: Flurries continue with another 5-15 cm of snow, 30-60 km/h wind from the northeast, alpine temperatures around -18 C.

Avalanche Summary

The most likely place for avalanches right now is on slopes where the wind has blown snow into wind slabs. This MIN report from Saturday describes several thin wind slabs that were triggered by riders in the Harvey Pass area. Similar type of activity can be expected throughout the week. 

Observations are limited this time of year, so there is a fair bit of uncertainty about the extent of current avalanche activity. Please consider sharing your observations on the Mountain Information Network (MIN).

Snowpack Summary

Scattered flurries and cold windy weather will form wind slabs in open terrain over the next few days. The snowpack is thin with many rocks and trees sticking out. The snowline starts around 1500 m, with about 40 cm of snow at 1700 m, and 50 to 100 cm of snow in the alpine.

5-15 cm of recent snow has accumulated over two crusts found in the middle and near the base of the snowpack. There is uncertainty about how the snow is bonding to these crusts, and they may act as a sliding layer for snow above them. Be prepared to back off to mellow terrain if you encounter signs of instability such as whumpfs or shooting cracks, which could indicate these layers are capable of producing avalanches.

Problems

Wind Slabs

An icon showing Wind Slabs

The weather forecast calls for more snow and wind, so watch for blowing snow and be cautious around freshly loaded slopes. Ridgetops and alpine terrain are the most likely spots to find wind slabs.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 1.5

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

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