Avalanche Forecast

Issued: Mar 26th, 2020 5:00PM

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

Avalanche Canada dsaly, Avalanche Canada

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Avalanche hazard will increase as new snow and elevated winds develop a surface instability around the region.

Summary

Confidence

Low - Uncertainty is due to the limited number of field observations. Forecast precipitation (either snow or rain) amounts are uncertain.

Weather Forecast

Thursday night: Cloudy with scattered flurries, up to 10 cm. Alpine low temperature -3 C. Moderate southwest wind.

Friday: Cloudy with scattered flurries, 5-10 cm. Alpine high temperature -4 C. Moderate to strong west wind.

Saturday: Flurries and snow, 10-20 cm. Alpine high temperature -5 C. Light to moderate southwest wind.

Sunday: Flurries and snow, 10-20 cm. Alpine high temperature -4 C. Light southeast wind with strong gusts.

Avalanche Summary

A recent large (size 2.5) natural glide slab release was observed on Tuesday. The debris from the release overran the John Little Falls hiking trail. 

Natural glide slab activity has been a regular occurence during recent periods of daytime warming, reinforcing the importance of avoiding glide cracks and areas exposed glide slab hazards.

Snowpack Summary

Flurries will be quickly impacted by increasing winds, redistributing loose snow and building slabs. Surface conditions over the region are likely a mix of recent wind slabs and wind-affected snow as well as melt freeze crust on south aspects and below about 1100 metres.

A layer of surface hoar crystals is buried around 30-60 cm in sheltered areas at and below treeline, shallow enough for human triggering on steep slopes where it is preserved. Recent observations of this layer are lacking.

An early-season layer of faceted grains and a melt-freeze crust can likely be found near the base of the snowpack at high elevations. A large load, such as a large cornice fall, may have potential to trigger it.

Terrain and Travel

  • Storm slab size and sensitivity to triggering will likely increase through the day.

Problems

Storm Slabs

An icon showing Storm Slabs

Flurries falling with westerly winds will redistribute loose snow and encourage slab development. Forecast amounts vary, meaning hazards may range from small wind slabs forming on leeward slopes to more widespread storm slabs affecting most avalanche terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

A weak layer of surface hoar crystals is buried around 30 to 60 cm deep in sheltered, shady terrain around treeline. It was reactive to both human and natural triggers last week and there is uncertainty about whether it is still a problem.

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

Elevations: Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2.5

Valid until: Mar 27th, 2020 5:00PM

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