Avalanche Forecast
Issued: Nov 30th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
swerner,
Avalanche Canada
Wind slabs on leeward slopes may be reactive to human triggering, especially in steep unsupported terrain features. The afternoon sun may have enough punch to weaken snow surfaces, especially on steep south slopes. Heads up for changing conditions.
Summary
Confidence
Moderate - Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack.
Weather Forecast
High pressure builds off the coast on Tuesday bringing a mix of sun and cloud. Wednesday afternoon may see a temperature inversion above 2000 m.
Monday Night: Light snow expected up to 5 cm. Strong WNW winds in the alpine.Â
Tuesday: Mix of sun and cloud. Alpine temperatures near -2. Strong ridgetop winds from the WNW. Possible Alpine temperature inversion bringing warm air above 2000 m.
Wednesday: Mostly cloudy with some sun. Alpine temperatures near 0 degrees or warmer if the inversion is strong. Ridgetop winds light from the East.
Thursday: Mix of sun and cloud. Alpine temperatures near -2. Ridgetop winds light from the southwest.
Avalanche Summary
Observations are limited right now, but there have been no reports of recent avalanches. We appreciate the recent reports submitted to the Mountain Information Network. Keep them coming!
Snowpack Summary
Wind slabs have formed in open terrain as last weeks 10 to 20 cm of snow is redistributed and formed into more cohesive slabs. These slabs may sit above a layer of surface hoar in sheltered terrain and above a hard crust in other areas.
Surface snow conditions may change with forecast sunshine and warmer temperatures up high on Tuesday afternoon and Wednesday. Surface snow may be moist and reactive on sunny slopes then re-freeze overnight into a crust. Â
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.Â
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
- Avoid areas where the snow feels stiff and/or slabby.
- Avoid freshly wind loaded terrain features.
- Be alert to conditions that change with elevation and sun exposure.
Problems
Wind Slabs
Watch for freshly formed wind slabs in the alpine, and open "alpine like" features at treeline. These slabs may be poorly bonded to underlying crust and surface hoar layers, although the distribution of these layers is uncertain. Surface snow may become reactive with afternoon sun, especially on steep solar aspects.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 1st, 2020 4:00PM
