Avalanche Forecast

Issued: Jan 11th, 2013 8:18AM

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

catherine brown, Parks Canada

Glacier.

Don't let sunny skies cloud your good judgement today.. a variety of hazards are present in the park, including a touchy buried persistent weak layer. Watch for solar triggered avalanches this afternoon on south through west facing slopes.

Summary

Weather Forecast

A ridge of high pressure builds in today bringing a NW flow brings cold, dry conditons. A weak inversion is forecast today with possible valley cloud and sunny conditions above.

Snowpack Summary

70cm of storm snow overlies a weak layer of buried surface hoar. The surface hoar sits on a crust which is best developed on steep S/SW slopes. The surface hoar layer was the largest in sheltered areas between 1500 and 1700m. This layer is more prominent on the eastern side of the park. This variability will make hazard evaluation tricky.

Avalanche Summary

Yesterday along the highway corridor we did not observe any new natural avalanches. However, visibility was poor. Avalanche control on Wednesday triggered numerous avalanches, mainly size 2-2.5. These avalanches primarily involved storm snow. We have had limited observations In the backcountry, however a widespread natural cycle is suspected.

Confidence

Due to the number of field observations

Problems

Persistent Slabs

A persistent weak layer down 50 to 70cm is reactive to skier triggering. Our observations suggest the most reactive locations are steep S/SW facing slopes and open glades. Strong south winds may have created harder wind slabs at and above treeline.

Dig down to find and test weak layers before committing to a line.Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Loose Dry

Up to 70 cm of loose storm snow is easily triggered by riders in steep terrain. Watch for fast sluffing especially in steep open glades where a surface hoar layer makes for easy sliding. Manage your travel accordingly.

Watch for terrain traps where small amounts of snow will acumulate into deep deposits.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 12th, 2013 8:00AM