Avalanche Forecast

Issued: Feb 29th, 2024 4:00PM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs and Persistent Slabs.

Avalanche Canada mhalik, Avalanche Canada

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630am update: Significant overnight snowfall concentrated in the south has increased avalanche danger for Friday. Keep decision-making conservative in the wake of the storm.

Summary

Confidence

Moderate

Avalanche Summary

On Thursday the field team reported seeing several size 1 and 2 slab avalanches in the Memekay Peak area. Recent small slabs (size 1-1.5) were also seen on north and east aspects at treeline in the Mt.Washington area.Natural avalanche activity is expected to continue with the stormy weather, and the potential for human triggering is considered very likely.

Snowpack Summary

Storm totals will vary from 50 cm to over 1 m in the west by Friday afternoon. Storm snow continues to build over a widespread crust in most areas, except in the north where storm snow will fall on heavily wind-affected snow.

The mid and lower snowpack is generally moist and well consolidated. A layer of facets exists between two crusts in the mid snowpack, we are uncertain how this layer will react to the heavy load of new snow.

Below treeline areas have now received enough snow to produce avalanches. Watch for "early season" type hazards such as shallowly buried stumps, creeks, and rocks.

Weather Summary

Thursday Night

Cloudy with 4 to 13 cm expected in south and western areas. 40 km/h southwest ridgetop wind. Treeline temperature -7°C. Freezing levels drop to 500 m.

Friday

Cloudy with 3 to 10 cm of snow. 30 to 40 km/h southerly ridgetop wind. Treeline temperature -6 °C. Freezing level 600 m.

Saturday

Cloudy with 2 to 10 cm of snow. 10 to 20 km/h southwest ridgetop wind. Treeline temperature -5 °C. Freezing level 800 m.

Sunday

Cloudy with 5 to 10 cm of snow. 25 to 40 km/h southeast ridgetop wind. Treeline temperature -6 °C. Freezing level 700 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Use increased caution at all elevations. Storm snow is forming touchy slabs.
  • As the storm slab problem gets trickier, the easy solution is to choose more conservative terrain.
  • Storm slabs in motion may step down to deeper layers resulting in large avalanches.

Problems

Storm Slabs

An icon showing Storm Slabs

Storm slabs exist on all aspects but will be most reactive on lee northwest though northeast features.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs

A weak layer of facets above a crust persists in the snowpack in isolated areas. Storm slab avalanches may step down to this layer resulting in very large, destructive avalanches.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Mar 1st, 2024 4:00PM

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