Avalanche Forecast

Issued: Nov 19th, 2023 4:00PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is early season. Known problems include Wind Slabs and Persistent Slabs.

Avalanche Canada MH, Avalanche Canada

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Strong wind and new snow will keep the avalanche hazard elevated. Watch for pockets of wind slab above tree line and in the alpine.

Early season hazards exist everywhere.

The Winter Permit System started on Nov 16! Take the quiz, get your annual permit, and know what areas are open before you venture into the backcountry.

Summary

Confidence

Low

Avalanche Summary

No new observations on Sunday, but visibility was poor. I suspect there was some activity in the alpine due to the strong winds.

Several natural sz 2.0 avalanches were observed Friday in Lone Pine, Single Bench, Lens, Cougar Valley and Gunners 2. Daytime warming and solar input also released small point release avalanches on solar aspects.

Snowpack Summary

The height of snow at treeline is ~90cm. A thin crust on steep solar aspects has been buried by 5-10cm of new snow.

The bottom of the snowpack is facetted and offers little support to the shallow snowpack, often settling and producing large "whumpfs". Snow depth increases with elevation but distribution is highly variable, expect many rocks/trees lurking at and just below the snow surface.

Weather Summary

Cloudy with sunny periods for Monday with SW winds up to 40 kph and an alpine high of -1. Freezing level expected to rise up to 1200m. No snow is forecasted.

Tuesday freezing levels will rise, with a pocket of warm air sitting between 1800-2500m. Winds are expected to be 40-65kph from the West.

Detailed weather forecasts can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
  • Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.

Problems

Wind Slabs

An icon showing Wind Slabs

New snow and strong southerly winds have formed pockets of fresh wind slab. If triggered, it may step down to the facetted layer at the base of the snowpack, resulting in a large avalanche.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

The facet layer at the base of the snowpack is more likely to be triggered in shallow, rocky areas, such as ridge-crests and open, convex slopes. A bridging crust exists below Treeline, preventing folks from sinking to the ground at lower elevations.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2.5

Valid until: Nov 20th, 2023 4:00PM

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