Avalanche Forecast

Issued: Feb 7th, 2018 4:37PM

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

Avalanche Canada swerner, Avalanche Canada

Storm snow amounts will vary across the region. The Coquihalla will see higher amounts then the Duffy. Avoid avalanche terrain.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Thursday

Weather Forecast

Thursday: 15-30 cm overnight Wednesday at upper elevations, with the higher accumulations being in the southern part of the region. 5-15 cm Thursday morning tapering off by early afternoon. Ridgetop winds strong from the southwest. Alpine temperatures near -5 with freezing levels 1300 m. Friday: Mix of sun and cloud with alpine temperatures near -8 and freezing levels at valley bottom. Ridgetop winds light from the north. Saturday: Mostly clear with no forecast snow. Alpine temperatures near -10 and ridgetop winds light from the northeast.

Avalanche Summary

On Tuesday, no new avalanche observations were reported from the northern part of the region (Duffy). In the south (Cascades) numerous glide avalanches up to size 3 were reported. Glide releases have a higher likelihood of failing when the ground cover is smooth bedrock or grass. Other avalanches to note from the south include wet slab avalanches up to size 2.5 with one reported as a size 3 from a steep southeast slope near 1700 m. Natural avalanches are likely with forecast storm snow, rain at lower elevations and strong ridgetop winds.

Snowpack Summary

Recent snowfall totals are highly variable. In the south, up to 20 cm of new snow fell bringing the alpine totals up to 40 cm since the weekend. In the north, new snow totals are half that and rapidly decreasing below 1800m. This new snow sits on old wind slabs in alpine locations and has buried a crust at treeline. At lower treeline and below elevations, warm temperatures (and rain in many locations) have created heavy snow conditions. This new snow adds to the 80-150 cm mid pack that sits above the mid- January crust, which generally shows signs of bonding. I would still remain suspect of this deeper layer, especially now, with additional load stressing the snowpack. Large fragile cornices could also act as a trigger on the slope below.

Problems

Storm Slabs

An icon showing Storm Slabs
New storm snow accumulations will build touchy storm slabs, especially on leeward slopes where more wind loading occurs.
Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Cornices

An icon showing Cornices
Recent snowfall and strong winds have created large fragile cornices. Cornices are unpredictable and demand respect. Give them a wide berth from above and below. Know what is lurking above you.
Give cornices a wide berth when traveling on or below ridgesFalling cornices may trigger large avalanches on slopes below.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1.5 - 2.5

Valid until: Feb 8th, 2018 2:00PM

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