Avalanche Forecast

Issued: Dec 13th, 2013 8:17AM

The alpine rating is high, the treeline rating is high, and the below treeline rating is high. Known problems include Storm Slabs and Loose Wet.

triley, Avalanche Canada

Northwest Coastal.

Forecast heavy precipitation, very strong winds, and rising freezing levels will result in High avalanche danger at all elevations.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Tonight and Saturday: Continued warming with freezing levels remaining at about 1500 metres. Expect 15-30 mm of precipitation overnight and another 20-30 mm during the day. Very strong Southwest winds during the storm.Sunday: A moist onshore flow will bring continued snow at higher elevations. The snow line should start lowering during the day, with very strong Southwest winds continuing during the day. Freezing levels dropping back down to about 800 metres by the evening.Monday: Some flurries combined with strong Southwest winds. Freezing levels at about 600 metres.

Avalanche Summary

The warm new storm snow is not expected to bond well to the shallow weak snowpack. Expect natural avalanche activity and easy triggering from skiers and sledders. Steep terrain at lower elevations may experience a cycle of moist or wet natural avalanches releasing at or near the ground, due to forecast rain falling on snow.

Snowpack Summary

Warm and wet Pacific moisture continues to build a storm slab at higher elevations. Rising freezing levels and continued precipitation are expected to create a moist slab above recent buried weak layers that may continue to release naturally. Rain on snow at lower elevations is expected to saturate the shallow snowpack. Very strong to extreme winds are creating deep pockets of wind transported snow at higher elevations.

Problems

Storm Slabs

The storm continues to develop a deep storm slab at higher elevations due to very strong winds and heavy precipitation.

Minimize exposure during periods of heavy loading from new snow, wind.>Use conservative route selection, stick to moderate angled terrain with low consequence.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 5

Loose Wet

Rain at lower elevations may saturate the snowpack resulting in moist or wet avalanches.

Minimize exposure during periods of heavy loading from rain on snow.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Dec 14th, 2013 2:00PM