Avalanche Forecast

Issued: Mar 5th, 2021 4:00PM

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

Avalanche Canada kdevine, Avalanche Canada

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Wind slabs are likely to be encountered at upper elevations and may be reactive to human triggering, especially in lee features.

Summary

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

FRIDAY NIGHT - Mainly cloudy with isolated flurries / moderate southwest wind / alpine low temperature near -7 

SATURDAY - Cloudy with sunny periods and isolated flurries / moderate southwest wind / alpine high temperature near -6 

SUNDAY - Mainly cloudy with isolated flurries / light southeast wind / alpine high temperature near -6 

MONDAY - A mix of sun and cloud / light west wind / alpine high temperature near -7

Avalanche Summary

On Thursday, there were a few small, natural loose wet avalanches reported at low elevations. There were also two natural storm slab avalanches, size 2 and 3, reported in the Howson Range.

On Wednesday there were no new avalanches reported for most of the region. There was a natural avalanche cycle in the Howson Range, which likely received recent snowfall amounts that were more in line with the amounts received in the Northwest Coastal region.

Last Sunday, a few natural wind slab avalanches were reported up to size 2 at treeline and in the alpine on northeast and northwest aspects. Wind slabs were also easily triggered on leeward slopes by the weight of a person. Numerous loose wet avalanches were observed from steep terrain features. 

Snowpack Summary

The region has received 30-40 cm of new snow over the past week with strong winds. Windward slopes have been scoured down to rocks in some areas. Wind slabs may be reactive on leeward slopes at upper elevations. Solar aspects may have a thin sun crust and below treeline the surface is likely a melt-freeze crust.

60-90 cm of snow sits on a variety of old snow interfaces consisting of hard wind-affected snow in exposed terrain and weak, faceted snow or possibly surface hoar in sheltered terrain. Recent reports suggest that the new snow is bonding to these layers.

Faceted snow at the base of the snowpack exists in much of the region. 

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Problems

Wind Slabs

An icon showing Wind Slabs

Moderate southwest winds are expected to continue and may form fresh and reactive wind slabs in leeward terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Mar 6th, 2021 4:00PM