Avalanche Forecast

Issued: Mar 7th, 2022 4:00PM

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

Avalanche Canada mconlan, Avalanche Canada

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A persistent slab problem requires diligence and a conservative mindset.

Summary

Confidence

High - Confidence is due to a stable weather pattern; little change is expected for several days.

Weather Forecast

MONDAY NIGHT: Cloudy with isolated flurries, trace accumulation, 10 km/h north wind, alpine temperature -4 C, freezing level 1300 m.

TUESDAY: Clear skies with no precipitation, 20 km/h north wind, alpine temperature -9 C.

WEDNESDAY: Clear skies with no precipitation, 10 km/h northeast wind, alpine temperature -13 C.

THURSDAY: Mix of sun and cloud with no precipitation, 10 km/h west wind, alpine temperature -8 C.

Avalanche Summary

The weekend saw various avalanche types, including some wind slabs at high elevations, many small wet loose avalanches, and a few persistent slab avalanches. The most concerning avalanches are the persistent slabs, which released on the weak layer described in the Snowpack Summary. The avalanches occurred on north to northeast aspects in alpine terrain. They avalanches propagated far, around 200 to 300 m.

Looking forward, it remains possible that persistent slab and wind slab avalanches could be triggered. Naturally-triggered avalanches may be on the decrease as the weather cools, but human triggering is possible.

Snowpack Summary

A dusting of snow sits on a surface melt-freeze crust on all aspects below around 1500 m and on sun-exposed slopes into the alpine. Dry snow remains on shaded slopes above around 1500 m. Recent northerly wind may form wind slabs in lee terrain features at higher elevations, which may rest on the crust.

Around 30 to 60 cm deep, a weak layer of sugary faceted grains may be found above a melt-freeze crust that formed in February. This layer has produced various human-triggered and natural avalanches over the past week. Activity has been most prevalent on northeast to northwest aspects at treeline and alpine elevations. Check out this forecaster blog for more info.

There are no deeper concerns at this time.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Be aware of the potential for large avalanches due to the presence of a persistent slab.
  • Be aware of the potential for wide propagation.
  • Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.

Problems

Persistent Slabs

An icon showing Persistent Slabs

A weak layer of faceted grains above a hard melt-freeze crust may be found around 30 to 60 cm deep. This layer continues to produce large avalanches that have the potential to propagate far. It is most likely to be triggered on northwest to northeast aspects at treeline and alpine elevations.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Wind Slabs

An icon showing Wind Slabs

Northerly wind may form wind slabs on southerly slopes. Where slabs form, they could be particularly touchy if they rest on a hard melt-freeze crust.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 8th, 2022 4:00PM