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Avalanche Forecast

Archived

Nov 21st, 2024–Nov 22nd, 2024

Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

Purcells, East Purcell, West Purcell.

A tricky avalanche problem exists. If triggered it could be very dangerous.
Stick to low-angle slopes free from terrain traps.

Confidence

Low

Avalanche Summary

No new avalanches were reported on Wednesday or Thursday.

On Tuesday, 2 large (size 2) avalanches were triggered in the alpine near Invermere. They failed on a crust with facets near the base of the snowpack. Also, numerous small and large (size 1-2.5) natural storm slabs were seen near Jumbo.

Snowpack Summary

Up to 50 cm of recent snow sits on a layer of surface hoar on shaded slopes, or a thin crust on sunny slopes.
Near the base of the snowpack there is a crust from early November. In shallower spots, facets have been found on the crust and avalanches have been occurring on this layer.
Typical snowpack depths in the alpine are 80-120 cm.

Weather Summary

Thursday Night

Cloudy with 2 cm of snow. 10 to 20 km/h south ridgetop wind. Treeline temperature -8 °C.

Friday

Cloudy with 5 to 10 cm of snow. 10 km/h southeast ridgetop wind. Treeline temperature -5 °C.

Saturday

Mix of sun and cloud with up to 5 cm of snow. 5 km/h west ridgetop wind. Treeline temperature -5 °C.

Sunday

Mix of sun and cloud with up to 5 cm of snow. 10 km/h west ridgetop wind. Treeline temperature -6 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Choose simple, low-angle terrain without steep convex rolls.
  • Avoid terrain traps such as gullies and cliffs where the consequence of any avalanche could be serious.
  • Avoid lee and cross-loaded slopes in the alpine.

Problems

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.