Avalanche Forecast

Issued: Nov 23rd, 2017 6:06PM

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

cgarritty, Avalanche Canada

Northwest Coastal.

Although forecast confidence is low, there is certainty that recent heavy snowfall and ongoing loading is elevating avalanche danger in the region. Please post your observations to the Mountain Information Network. (MIN)

Summary

Confidence

Low - Due to the number of field observations

Weather Forecast

Thursday night: Flurries bringing approximately 10 cm of new snow. Moderate to strong southwest winds.Friday: Flurries bringing 5-15 cm of new snow. Strong to extreme southwest winds. Freezing level to 800 metres with alpine temperatures around -4.Saturday: Continuing flurries bringing 10-15 cm of new snow. Moderate to strong southeast winds. Freezing level to about 700 metres with alpine temperatures around -3Sunday: Scattered flurries bringing 5-10 cm of new snow Moderate to strong south winds. Freezing level to about 700 metres with alpine temperatures of about -5.

Avalanche Summary

No new avalanche activity has been reported, but this lack of information does not represent benign conditions. Watch for the presence and sensitivity of storm slabs to increase with elevation and please post your observations to the Mountain Information Network (MIN)

Snowpack Summary

50-60 mm of precipitation fell over the region over Wednesday, accompanied by moderate to strong winds and freezing levels around 800 metres. Under these conditions, new snow accumulations of up to 60 cm may now form our upper snowpack at upper elevations. New snow depths and wind effect will increase with elevation. Although the composition of the mid and lower snowpack in the region is uncertain, rapid loading of the upper snowpack carries the potential to activate weaker layers that are likely to have formed during the early season.

Problems

Storm Slabs

Recent stormy weather likely formed thick new storm slabs at upper elevations. These are expected to remain reactive over the near term. A storm slab release may have the potential to step down to deeper weak layer to produce a very large avalanche.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.The new snow will require several days to settle and stabilize.If triggered, storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

2 - 3

Loose Wet

As snow stacked up at higher elevations, rain saturated the snowpack below treeline. Danger from loose wet avalanches exists where surface snow remains moist - especially in steep terrain.

Be cautious of sluffing in steep terrain, particularly where the debris flows into terrain traps.Use extra caution on steep slopes if the snow is moist or wet.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Nov 24th, 2017 2:00PM