Avalanche Forecast

Issued: Dec 20th, 2014 8:01AM

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

andrew jones, Parks Canada

Glacier.

Use extra caution at higher elevations and wind-exposed areas. The recently minted storm slab is poorly bonded to a reactive SH layer.

Summary

Weather Forecast

Cloudy skies with flurries are expected for this morning and early this afternoon with freezing levels remaining below 1400m. A strong low pressure system is expected to bring strong SW winds and heavy precipitation to the area later this afternoon and into the evening.

Snowpack Summary

20-30cm of new snow has buried large surface hoar which sits on a rain crust to 2100m and on settled snow above 2100m. Overnight winds have likely consolidated new snow into storm slabs at higher elevations. Well settled mid-pack with 30cm crust/facet basal weakness.

Avalanche Summary

No new avalanches were observed in the Highway Corridor. We received a report of a natural avalanche in Cheops North #4, running to the creek in Connaught Creek drainage.

Confidence

Problems

Storm Slabs

This SH layer now sits below 20-30cm of new snow. A storm slab is developing at higher elevations and wind-exposed areas. These slabs will bond poorly to the SH interface. Avalanches on this layer may run farther than expected, easily entrain snow.

Use caution in lee areas in the alpine and treeline. Recent storm snow has formed touchy slabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 3

Persistent Slabs

The November crust weaknesses at the bottom of the snowpack are difficult to trigger, but if they fail the consequences will be very high.

Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 3

Valid until: Dec 21st, 2014 8:00AM