Avalanche Forecast

Issued: Feb 10th, 2015 8:51AM

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

rbuhler, Avalanche Canada

Cariboos.

Residual storm instabilities may still be a concern, especially in the alpine. Avoid steep unsupported slopes and wind-loaded features. If the sun comes out, use extra caution on south-facing slopes.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

A dirty ridge of high pressure should keep things mainly dry on Wednesday but light scattered flurries are possible. Mostly cloudy conditions are expected but sunny breaks are possible. Freezing levels are forecast to be around 1600m and alpine winds light-to-moderate from the SW. On Thursday, mostly cloudy conditions are expected during the day. Freezing levels are forecast to rise to over 2000m. Light precipitation is forecast for Thursday night and models are currently showing 5-10mm. On Friday, mostly cloudy and mainly dry conditions are expected. Freezing levels may peak on Friday at over 2500m.

Avalanche Summary

Widespread natural, human-triggered, and explosive controlled avalanches up to size 3 were reported on Friday through Monday during the storm. This includes both storm slabs and persistent slabs. On Wednesday, natural activity is generally not expected but is possible on steep south-facing slopes if the sun comes out. Human-triggering of the storm slab remains possible, especially on steep slopes and wind loaded features in the alpine.

Snowpack Summary

60-90cm of rapidly settling storm snow sits over the late-Jan weak layer at higher elevations. Rain has soaked the snow surface up to around 1700m and moist snow is reported to at least 2000m. Overnight cooling may be refreezing the snow surface forming a weak crust at some elevations. Strong SW winds had formed wind slabs in exposed leeward terrain features. The storm slab sits on an old rain crust at lower elevations, variable surface hoar, and/or wind affected surfaces at higher elevations. The mid-January surface hoar is typically down 80-120cm and has been reactive in some areas. The mid-December weak layer is down over 120cm but was generally unreactive through the storm.

Problems

Storm Slabs

Strong winds, heavy snowfall, and high freezing levels over the weekend created widespread storm slabs at higher elevations. These slabs are expected to be gaining strength but may remain reactive to human-triggering for several days.

The widespread storm slabs will require several days to settle and stabilize. >Stay off recent wind loaded areas until the slope has had a chance to stabilize.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 5

Persistent Slabs

The mid-Jan buried persistent weak layer has become reactive with recent storm loading and may remain sensitive for several more days. Smaller avalanches or cornice falls may step-down to this layer resulting in very large avalanches.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Be aware of thin areas that may propogate to deeper instabilites.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Loose Wet

Loose wet avalanches are possible from steep terrain features where the snow surface is moist. If the sun comes out, sluffing from steep sun exposed slopes is possible.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Be cautious of sluffing in steep terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Feb 11th, 2015 2:00PM