Avalanche Forecast

Issued: Jan 14th, 2018 3:31PM

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

Avalanche Canada jfloyer, Avalanche Canada

A Special Public Avalanche Warning is in effect for this region. Continued warm temperatures and sunshine are expected to maintain elevated avalanche danger.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain on Monday

Weather Forecast

Monday: A mix of sun and cloud with warm air remaining at higher elevations and cold air remaining in the valleys. Freezing level 3000m. Light southeasterly winds.Tuesday: Cloud increasing. Light rain or snow in the afternoon, 2-4 mm. Freezing level dropping from around 2500m in the morning to around 1800m in the afternoon. Moderate southerly winds.Wednesday: Light snow, around 5 cm, increasing in the evening. Freezing level around 1400m. Moderate southerly winds.

Avalanche Summary

Very significant avalanche activity occurred in the region last Wednesday and Thursday. A smaller avalanche cycle, mostly affecting the recent storm snow was reported on Saturday. While the weather remains warm, there is still an increased likelihood of triggering something large.

Snowpack Summary

Warm alpine temperatures have made the snow surface moist on slopes that face the sun. Below the surface, 40 to 60 cm of recent snow has settling into a cohesive slab on top of the reactive January 5th interface which consists of a crust/surface hoar combination on steep southerly aspects and pure surface hoar on remaining aspects. The late December surface hoar also remains reactive and is now down 50 to 90 cm below the surface. Adding to the complexity of the mid to upper snowpack is the mid-December surface hoar which is now 60 to 120 cm below the surface. This spooky interface continues to produce sudden snowpack test results and is most pronounced at treeline, but is also present below treeline. The overlying slab is now deep, dense and destructive. Two laminated crusts created by rain events in late November lay just below the mid-December interface, and may co-exist with facets. In shallow, rocky terrain the mid-December surface hoar and the late November crust seem to be reacting together which is a volatile combination.

Problems

Persistent Slabs

An icon showing Persistent Slabs
Our complex snowpack is currently producing very large and destructive avalanches on up to four separate weak layers buried 50 to 120cm below the surface. Expert level knowledge and experience is required to safely venture into the backcountry.
Only the most simple non-avalanche terrain free of overhead hazard is appropriate at this timeAvoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 4

Loose Wet

An icon showing Loose Wet
Warm temperatures and sunshine are expected to destabilize slopes that face the sun on steep terrain.
Small sluffs may step down to deeper layers resulting in large avalanches.

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Valid until: Jan 15th, 2018 2:00PM