Avalanche Forecast

Issued: Jan 12th, 2013 8:00AM

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.

A highly variable weak layer was buried recently from the last storm.. it is still time to move carefully into bigger terrain.

Summary

Weather Forecast

A ridge of high pressure continues to bring cold and dry conditions with a northwest flow. Expect a high of -15 in the alpine today and light NW ridge top winds.

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 grew largest in sheltered areas (1500 to 1700m). This layer is more prominent on the eastern side of the park. This layer will be most reactive on the specific terrain described above.

Avalanche Summary

Yesterday along the highway corridor we did not observe any new natural avalanches. Avalanche control on Wednesday triggered numerous avalanches, mainly size 2-2.5. These avalanches primarily involved storm snow. Few backcountry observations suggest a large natural cycle occurred during the storm.

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.

Carefully evaluate big terrain features by digging and testing on adjacent, safe slopes.Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

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.

Avoid travelling on ledges and cliffs where sluffing may have severe consequences.Watch for terrain traps where small amounts of snow will acumulate into deep deposits.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Jan 13th, 2013 8:00AM