Archived

Avalanche Forecast

Dec 12th, 2014–Dec 13th, 2014

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

2: Moderate

The avalanche danger rating below treeline will be moderate

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

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Glacier.

Spring like conditions will persist for one more day until temperatures cool down. Expect the hazard to stay elevated until this happens.

Weather Forecast

The warm storm is finally leaving the interior by the end of today as a high pressure ridge builds over the Province. Expect temperatures to cool down and skies to clear into the weekend. Lingering flurries/rain for today.

Snowpack Summary

Another 4.2mm of rain at Rogers Pass. Above 2000m up to ~25cm of recent storm storm snow. This is a high density slab that overlies the Dec 5 surface hoar/sun crust layer. Loading on lee slopes from the strong south winds associated with the storm should be expected. The Nov persistent weak layers are down ~105 and ~140cm.

Avalanche Summary

Natural avalanche activity continued yesterday within the highway corridor with numerous size 2-3.0 avalanches occurring from all aspects and running onto avalanche fans. Avalanche debris is wet in character. A natural cycle is expected in the backcountry as well but observations are limited at this time.

Confidence

Due to the number of field observations

Avalanche Problems

Storm Slabs

A heavy storm slab that formed over the past 3 days will bond poorly to the snow below. Large natural avalanches have been occurring, running into valley bottoms. Storm slabs may step down to deeper instabilities.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 2 - 3

Persistent Slabs

Continued warm temperatures and rain at lower elevations are ideal to wake up buried persistent weak layers capable of wide propagations and producing very large and destructive avalanches.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 2 - 3

Wet Slabs

Rain to at least 1900m has weakened the upper snowpack and is likely to be saturated at the lower elevations.

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Possible - Likely

Expected Size: 1 - 3