Avalanche Forecast
Issued: Nov 16th, 2019 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Deep Persistent Slabs.
Mark Herbison,
Parks Canada
A storm is brewing and though total snow/rain amounts are uncertain, avalanche activity will increase.
In areas that receive more than 25cm of new snow, treat the Danger Rating as High!
Summary
Weather Forecast
Sunday will see 10-30cm of snow depending on which forecast you're looking at... One thing they all agree on is that its going to warm and windy as the freezing level rises to 2100m with an alpine high of -1 (that means rain at lower elevations). The winds will range from 30-80km/hr from the SW. Snow, wind and temps tapering off on Monday.
Snowpack Summary
10-20cm of settled snow sits on the Nov 8 crust and a variety of old wind slabs in the alpine. Faceting observed around the Oct crust and at the ground showing sudden collapses & propagation propensity in deeper snowpack areas (70-90cm). Treeline snow depths range from 50-80 cm, and up to 110 cm wind loaded pockets in the alpine.
Avalanche Summary
Expect avalanche activity to increase throughout the day on Sunday as the storm progresses.
A skier accidental size 2 slide failed on facets on the ground on a convex feature in Pipestone Bowl, near the Lake Louise Ski area on Friday. Size 1.5 natural on basal facets NE aspect at 2400 m, base of Whitehorn gullies. No other recent observations.
Confidence
Intensity of incoming weather systems is uncertain on Sunday
Problems
Storm Slabs
A potentially touchy storm slab will develop Saturday night and through Sunday as a warm, wet and windy system moves through the region. Expect slab formation in exposed areas at treeline and lee features in gullies and along ridges.
- If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
- Use caution in lee areas in the alpine and treeline. Storm snow is forming reactive slabs.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
Reactive in the Louise area on Friday (see avalanche summary) on basal facets and the October crust. Pending on the intensity of the incoming system on Sunday, we expect this layer to become more active.
- Convex features and steep unsupported slopes will be most prone to triggering.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 17th, 2019 4:00PM
