Archived

Avalanche Forecast

Dec 13th, 2013–Dec 14th, 2013

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

4: High

The avalanche danger rating below treeline will be high

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Northwest Coastal.

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

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.

Avalanche 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