Avalanche Forecast

Issued: Mar 19th, 2022 4:00PM

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

Avalanche Canada wlewis, Avalanche Canada

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Avalanche danger is highest in the central and southern Cariboos. Conservative terrain choices are advised, buried weak layers still remain reactive on specific features. 

Minimize exposure to south facing slopes during strong sunshine, avalanche danger can rise rapidly. 

Summary

Confidence

Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.

Weather Forecast

SATURDAY NIGHT: Flurries continue, around 5 cm of snow. Freezing levels drop to valley bottom. Moderate southwesterly winds. 

SUNDAY: Mostly sunny with moderate southwest winds. Freezing levels reach 1200 m, alpine high of -4. 

MONDAY: Scattered flurries with partly cloudy skies. Moderate southwest winds. Freezing levels reach 1700 m. Alpine high of +1

TUESDAY: Mostly cloudy with scattered flurries. Strong southwest winds. Freezing levels remain high, reaching 2000 m. Alpine highs around +4.

Avalanche Summary

On Friday, a rider triggered size 1.5 slab avalanche was reported on the buried surface hoar on a convex roll at treeline.

Avalanche activity has been tapering off over the week, with natural activity observed on Thursday. On Wednesday large remotely triggered avalanches were reported on north and south aspects with impressive propagation. 

Small wet avalanches have been reported within the last 5 days, on all aspects below the freezing line and on sun affected slopes. 

Snowpack Summary

Up to 70 cm of recent settling storm snow sits over a layer of weak surface hoar in sheltered and shaded terrain, and over a crust on south facing slopes. The new snow is bonding poorly to this old surface in some areas, producing large avalanches within the last 5 days, and reactive results on testing. 

At higher elevations consistent southwest winds are creating deeper deposits on north through east facing features. Below 1500 m, moist snow or a melt-freeze crust likely exists from recent rain and warm temperatures.

The lower snowpack is generally well-settled and strong in most areas, with crust layers 50 to 100 cm deep.

Terrain and Travel

  • Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.

Problems

Persistent Slabs

An icon showing Persistent Slabs

Buried weak layers continue to produce large natural and rider triggered avalanches. 

  • A layer of crust and facets can be found at all elevations on sun affected slopes (south through east) in most terrain. 
  • On shaded slopes, a layer of surface hoar may be preserved in sheltered treeline features. This layer is less widespread but still reactive. 

The most reactivity has been seen in Valemount and Blue River area. More information can be found here in the new forecaster blog. 

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1.5 - 3

Wind Slabs

An icon showing Wind Slabs

Recent snow and moderate southwest winds have formed wind slabs at higher elevations. 

These slabs may be surprisingly deep and propagate widely where they are sitting on a weak layer of surface hoar or a sun crust.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 20th, 2022 4:00PM