Avalanche Forecast

Issued: Mar 8th, 2017 4:17PM

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

jlammers, Avalanche Canada

Lizard-Flathead.

The best and safest riding will likely be found in sheltered, lower elevation terrain.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Thursday: 2-4cm of new snow / Light southwest winds / Alpine temperature of -10Thursday night and Friday: up to 25cm of new snow / Strong to extreme southwest winds / Alpine temperature of -7Saturday: Mix of sun and cloud / Moderate southwest winds / Alpine temperature of -3 / Freezing level at 1500m

Avalanche Summary

In the past two days at treeline and alpine, natural storm slab and loose dry avalanches to Size 2 have been reported on south through northeast aspects. Cornices are large and remain easy to trigger. A great image from Sunday illustrates just how surprising the results can be. Click here for details. Natural activity is expected to taper off on Thursday, but storm slabs are expected to remain sensitive to human triggering. Looking forward, natural storm slab activity is expected to ramp-up again in response to new snow and wind on Thursday night and Friday

Snowpack Summary

Another day, another 10-15 cm of snow falling: The weekly total now stands at roughly 130 cm. At times, strong southwest winds have extensively redistributed the snow and formed large brittle cornices. Over the weekend the new snow came in "upside down" (heavier, denser snow over lighter snow) and is rapidly settling into a slab which sits over a variety of old surfaces including surface hoar, facets, stiff wind slabs, sun crusts, and a rain crust below 1900 m.Isolated basal weaknesses may still exist in shallow snowpack areas and appear to isolated to north-northeast aspects in the alpine.

Problems

Storm Slabs

Although the brunt of the storm has passed, recently formed storm slabs will likely remain sensitive to human triggering on Thursday. Use increased caution in wind-exposed terrain.

Avoid leeward slopes as a thicker, reactive slabs will likely exist.The new snow will require several days to settle and stabilize.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Cornices

Cornices are huge and are ripe for triggering. To avoid a nasty ride, give these monsters a wide berth when traveling along ridge crests.

Extra caution needed around cornices with current conditions.Minimize exposure to overhead hazard from cornices.Even small cornice falls may trigger larger avalanches.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Mar 9th, 2017 2:00PM