Avalanche Forecast
Issued: Feb 15th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
wlewis,
Avalanche Canada
Manage open slopes at treeline with caution, persistent slab avalanches are most likely here.
Avalanches are unlikely where a thick surface crust exists.
Summary
Confidence
Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.
Weather Forecast
TUESDAY NIGHT: Partly cloudy with a light flurries. Moderate northwest winds with freezing levels at valley bottom.
WEDNESDAY: A mix of sun and cloud. Chance of flurries. Moderate northwest winds, alpine high of -3 with 1300m freezing levels.Â
THURSDAY: Increasing cloud. Chance of flurries. Strong northwest winds. Freezing levels rise toward 2000 m. Alpine high of +1.Â
FRIDAY: Cloudy with isolated flurries. Strong northwest winds. Freezing levels remain around 2000 m. Alpine high +2.Â
Avalanche Summary
Avalanche activity on the January 30th surface hoar weak layer increased last week as a result of the warmer temperatures, on all aspects at treeline elevations. This layer is now below a thick melt freeze crust in most areas. Cornice control using explosives occurred on Monday, without triggering slabs on the slope below.Â
Snowpack Summary
Up to 5 cm of new snow overlies a variety of surfaces. Higher elevations have been heavily wind effected, and a melt freeze crust exists on solar aspects to 2400 m. Lower elevations hold a widespread thick melt freeze on all aspects, surface hoar sits above the crust in sheltered terrain features.Â
The late January interface is buried 20-50cm deep, and consists of a melt-freeze crust at lower elevations and on solar aspects extending into the alpine. Surface hoar sits above the crust in sheltered areas at treeline and below.
Several surface hoar layers are now buried in the upper snowpack 40-120cm deep. The snowpack below is well consolidated, with the early-December crust/facet persistent weak layer buried 80-150 cm deep. It is currently considered dormant. We expect this layer to become active later this season, check out the forecaster blog for more information.
Terrain and Travel
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
- Be alert to conditions that change with aspect and elevation.
Problems
Persistent Slabs
- A layer of surface hoar from late January is buried 20-50 cm deep. On solar aspects and at lower elevations surface hoar sits over a melt freeze crust.
- Another layer of surface hoar/facets over a crust from early January is buried 60-100 cm deep.
Treat sheltered open slopes at a treeline with extra caution where the surface hoar is most likely to be preserved - like cut blocks. Deeper instabilities could be triggered in shallow snow pack areas or by a large load such as a cornice or step down avalanche.
Avalanche activity is less likely where a thick and supportive crust sits on the surface.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Feb 16th, 2022 4:00PM
