Avalanche Forecast

Issued: Mar 5th, 2016 9:10AM

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

jlammers, Avalanche Canada

Sea To Sky.

Forecast snowfall amounts for Saturday night vary greatly across the region. If more than 20cm falls in your riding area, the Avalanche Danger in the alpine may be HIGH.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Sunday

Weather Forecast

On Saturday night expect 10-15cm of new snow with another 10cm falling on Sunday. A mix of sun and cloud is forecast for Monday while light snowfall is expected on Tuesday. Winds should be extreme and southwesterly on Sunday, becoming mainly light on Monday and Tuesday. Freezing levels should hover between 1300 and 1500m for the forecast period.

Avalanche Summary

Backcountry observations have been limited due to inclement weather although I suspect there was a widespread round of storm slab avalanche activity in response to recent heavy snowfall and wind.

Snowpack Summary

Heavy snowfall on Friday (up to 50cm in 24 hours) and extreme southerly winds have formed deep and reactive storm slabs on lee and cross-loaded alpine and treeline features. On windward terrain, extensive scouring has been reported. Ongoing stormy weather has also encouraged extensive cornice growth. Recent storm totals (which vary from about 100cm to over 130cm) overlie a temperature crust, old wind slabs and spotty surface hoar. The mid and lower snowpack are generally strong and well-settled.

Problems

Storm Slabs

Continued stormy weather on Sunday will promote ongoing storm slab activity. Forecast extreme winds will encourage hard slab formation and wide propagations.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be aware of the potential for wide propagations due to the presence of hard windslabs.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Cornices

Cornices are reported to be very large and weak. Stay well back from ridgecrests, and watch your overhead hazard as a cornice fall could trigger a large avalanche on the slope below.

Give cornices a wide berth when travelling on or below ridges.>Do not travel on slopes that are exposed to cornices overhead.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

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