Avalanche Forecast

Issued: Feb 5th, 2016 7:23AM

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

Avalanche Canada triley, Avalanche Canada

Stormy conditions have elevated the avalanche danger to HIGH. Touchy storm slabs may take some time to settle and bond.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

Strong southerly winds and heavy precipitation overnight with the freezing level at about 1200 metres. Snow ending Saturday morning as the storm moves to the east, winds becoming moderate westerly and temperatures cooling as freezing levels drop to about 600 metres. Light southwest winds on Sunday with broken skies in the afternoon and freezing levels rising rapidly to 2500 metres. Clear skies and light southwest winds on Monday with freezing levels around 3000 metres.

Avalanche Summary

No new avalanches reported. Suspect poor visibility and travel conditions limited alpine observations. Observations from the Whistler area that start zones were easy to trigger, and storm slabs developed rapidly re-loading start zones throughout the day.

Snowpack Summary

Rain on Friday up to about 900 metres and moist snow up to 1600 metres. Strong to extreme southerly winds at 2000 metres and above developing storm slabs with heavy precipitation. Below the new storm slabs there is about 40 cm of recent snow above 60-80 cm of moist snow or a rain crust below 1800 metres. Cornices were already large before the new storm, and new growth is expected to be fragile. Where it still exists, the mid-January surface hoar layer may be found between 100 and 180 cm below the surface. The combination of heavy storm loading and warm temperatures has likely flushed out this weak layer in most areas. However, there is still some uncertainty regarding the sensitivity and distribution of this persistent avalanche problem, especially at high elevations in the north of the region where it remains reactive in snowpack tests (hard to initiate but sudden "pops" results).

Problems

Storm Slabs

An icon showing Storm Slabs
New storm slabs continue to develop with strong to extreme southerly winds and heavy snowfall.
Be cautious as you transition into wind affected terrain.>Minimize exposure during periods of heavy loading from new snow, wind.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Cornices

An icon showing Cornices
New cornice growth may be weak and fall off naturally. Avoid traveling beneath cornices.
Extra caution needed around cornices with current conditions.>Pay attention to overhead hazards like cornices.>

Aspects: North, North East, East, South East, South, South West.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Feb 6th, 2016 2:00PM

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