Avalanche Forecast

Issued: Apr 3rd, 2013 9:25AM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Cornices.

Avalanche Canada pmarshall, Avalanche Canada

Summary

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

Synopsis: The first in a series of frontal systems will reach the South Coast on Thursday afternoon spreading moderate to heavy precipitation through Saturday morning. Thursday: Increasing cloud with precipitation developing in the afternoon. 5-15 mm expected overnight. The freezing level is around 2000 m. Winds increase to moderate of strong from the southwest. Friday: Moderate to heavy precipitation – 15-20 mm. The freezing level drops to around 1600 m and winds are moderate to strong from the southwest. Saturday: Precipitation should ease off during the day and the freezing level continues to gradually drop.

Avalanche Summary

There were no new reports of avalanches on Tuesday. Recent avalanche activity included reports of loose wet sluffs up to size 2 on solar aspects and isolated cornice failures.

Snowpack Summary

Recent warm temperatures have created melt freeze conditions on all aspects below 2000m and to mountaintop on south facing terrain. Isothermal conditions as deep as 100cm have been reported on South aspects at lower elevations. On high north-facing slopes surfaces are well settled and surface hoar development continues in some areas. Cornices are huge and potentially weak. A layer of surface hoar (buried on March 11; now down about 60 cm) is still being observed in some locations. Triggering this layer has become unlikely, and would most likely require a large trigger or from a thin snowpack zone. Mid and lower snowpack layers are well bonded.

Problems

Cornices

An icon showing Cornices
Cornices are large and become more susceptible to failure due to warming. A cornice fall could possibly trigger a slab on slopes below.
Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 6

Valid until: Apr 4th, 2013 2:00PM

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