Avalanche Forecast

Issued: Jan 8th, 2012 3:00PM

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

Avalanche Canada ghelgeson, Avalanche Canada

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain

Weather Forecast

The warm front associated with the weekend storm has delivered surprisingly little precipitation to the Purcells. The ridge of high pressure that has been keeping the precip out slides to the south Sunday night allowing a cold front to impact the area Monday. I expect 5 - 10 cm out of this wave. Winds will switch from the W to NW late in the day Monday with enough oomph to create yet another round of windslab avalanche activity. Expect 1500 m temps to be near 0 C. A ridge of high pressure moves in Tuesday which should break up the cloud cover and provide some good visibility.

Avalanche Summary

A skier was killed in a size 3 avalanche in the Molar area of the Dogtooth range near Golden on Friday. The 4th skiers on the slope triggered the slide. On Saturday a skier triggered a size 3 avalanche in the alpine, the crown averaged 100cm in depth & the avalanche was reported to have run full path. The group had been skiing in the area all day without result until the accident happened.

Snowpack Summary

The latest batch of storms has delivered around 50 cm of snow to the region. In some locations the new snow rests on top of a surface hoar layer buried January 3rd. Strong southwesterly winds have redistributed the new snow into windslabs that can be found on NW through SE facing slopes at and above treeline. Widespread crossloading is present throughout the region. A rain / melt/freeze crust formed by recent warm temperatures can be found as high as 1600m. The mid-December surface hoar layer continues to be a player, it's now buried 80 - 140 cm below the snow surface. Very weak snow near the ground is also a concern and while it has not been reactive recently, triggering a full depth avalanche near the ground is within the realm of possibilities right now.

Problems

Wind Slabs

An icon showing Wind Slabs
Hard slabs capable of wide propagation exist. These slabs are likely to break above you. Winds switch from SW to NW Monday, so, you need to carefully evaluate each slope for windslab hazard.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

2 - 5

Storm Slabs

An icon showing Storm Slabs
A slab has developed during recent stormy weather that is above a weak surface hoar layer that developed over a short period of clear weather at New Year's. This slab in itself may produce avalanches up to size 3.0

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 5

Persistent Slabs

An icon showing Persistent Slabs
A deep slab rests on a touchy surface hoar weakness buried in mid-December. This layer is still sensitive and susceptible to rider triggered avalanches which will likely be large, destructive and may fracture across surprisingly far distances.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 7

Valid until: Jan 9th, 2012 8:00AM

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