Avalanche Forecast

Issued: Jan 13th, 2013 8:17AM

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

Parks Canada Danyelle magnan, Parks Canada

Be cautious as you transition into bigger terrain; the variable distribution of the persistent slab may surprise you with severe consequences. Rising temps over the next few days may increase avalanche danger by Tuesday.

Summary

Weather Forecast

High pressure and NW'ly flow continues. Expect alpine sun and valley cloud today, with light N'ly winds. Temps will be around -15. A warm front will move into the region overnight bringing clouds, flurries, moderate NW winds, and rapidly rising temps with alpine inversion temps of -3 on Mon. On Tues, expect some sun and temps up to -2.

Snowpack Summary

70cm of storm snow is settling into a cohesive slab which overlies the Jan.4 persistent layer. The distribution of this layer is variable, but tests indicate it is skier triggerable. It consists of surface hoar which is largest in sheltered areas between 1500 and 1700m, and a crust with facets or surface hoar which on steep S'ly slopes.

Avalanche Summary

There have been no new avalanches observed since Jan 10th. Avalanche control on Wednesday triggered numerous avalanches, mainly size 2-2.5. These avalanches primarily involved storm snow. Skiers have reported whumphing on steep south aspects where the sun crust is buried. On steep slopes, expect sluffing in the surface snow.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Problems

Persistent Slabs

An icon showing Persistent Slabs
A cohesive slab overlies a persistent weak layer. Variable distribution and composition makes this layer difficult to predict. Tests on this layer indicate it is skier triggerable and observations indicate it is most reactive on steep S'ly aspects.
Dig down to find and test weak layers before committing to a line.Choose well supported terrain without convexities.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Loose Dry

An icon showing Loose Dry
Cold temperatures is keeping the surface snow loose, especially on slopes sheltered from the wind. On steep slopes, this surface snow will sluff. On steep confined features (ie gullies) they may gain mass.
On steep slopes, pull over periodically or cut into a new line to manage sluffing.Avoid travelling on ledges and cliffs where sluffing may have severe consequences.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Jan 14th, 2013 8:00AM