Avalanche Forecast

Issued: Nov 27th, 2020 4:00PM

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

Avalanche Canada shorton, Avalanche Canada

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Be cautious in steep open terrain where the snow has been wind-affected. No significant snow expected for the next few days.

Summary

Confidence

Moderate - Confidence is due to a stable weather pattern with little change expected. Uncertainty is due to the limited number of field observations.

Weather Forecast

Clear and windy weather for the weekend.

FRIDAY NIGHT: Some light flurries with trace amounts of new snow, 40-70 km/h wind from the southwest, alpine temperatures around -5 C.

SATURDAY: Clearing skies throughout the day, moderate west wind in the morning then lighter wind in the afternoon, freezing level drops to valley bottom, alpine temperatures around -5 C.

SUNDAY: Clear skies, 30-50 km/h wind from the southwest, alpine high temperatures around -5 C.

MONDAY: Mix of sun and cloud, 30-50 km/h wind from the southwest, alpine high temperatures around -5 C.

Avalanche Summary

Observations are limited right now, but there have been no reports of recent avalanches. Over the next few days the surface snow could be blown into unstable slabs in steep open terrain.

We appreciate the recent reports submitted to the Mountain Information Network. Keep them coming!

Snowpack Summary

Snowpack depths at upper treeline elevations are nearing 100 cm and beginning to exceed the threshold for avalanches, while the snowpack is much thinner in the valleys. Windy conditions over the weekend will blow around the 10-20 cm of snow that fell on Tuesday night. There is potential for this snow to form unstable slabs on certain isolated slopes. This snow may sit above a layer of surface hoar in sheltered terrain and above a hard crust in other areas. If wind slabs form above these layers they could be particularly sensitive to triggering. The lower snowpack consists of crusts. Weak snow may be developing around these crusts in some areas, which will be a snowpack feature to monitor as the season progresses.

Terrain and Travel

  • Be careful as you transition into wind affected terrain.
  • Closely monitor how the new snow is bonding to the old surface.

Problems

Wind Slabs

An icon showing Wind Slabs

Wind may be blowing snow into unstable slabs in steep open terrain. These slabs may be poorly bonded to underlying crust and surface hoar layers, although the distribution of these layers is uncertain.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Nov 28th, 2020 4:00PM