Avalanche Forecast

Issued: Mar 11th, 2013 9:05AM

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

Avalanche Canada pmarshall, Avalanche Canada

The current storm track has the bulk of the incoming precipitation hitting the South and Central Coast. If the track slides a little further north we could see much more snow and higher avalanche danger.

Summary

Confidence

Poor - Track of incoming weather is uncertain for the entire period

Weather Forecast

Synopsis: A steady southwest flow will drive a series of disturbances onto the BC coast this week. There is some uncertainty regarding the track timing of each pulse of heavy precipitation. Currently it looks like Terrace and south will see decent precip amounts, but northern areas may be considerably drier. Tuesday: 5-10 cm. The freezing level is around 500 m. Winds are moderate to strong from the southwest. Wednesday: 5-10 cm. The freezing level is steady around 500 m and winds increase to strong from the southwest. Thursday: Moderate to locally heavy snow. The freezing level should rise to 1000-1200 m.

Avalanche Summary

Several natural size 1-2 wind slabs were observed out of exposed north and east aspects. There was also a report of a remotely triggered size 2 hard wind slab from an exposed NE aspect at treeline. This slide most likely failed on the recently buried surface hoar layer.

Snowpack Summary

Light to locally moderate amounts of new snow now overlie a variety of old surfaces which include: a crust at lower elevations and on solar aspects; old wind slabs in exposed areas, and fairly widespread large surface hoar. Moderate to locally extreme west/southwest winds have redistributed the new snow into soft and hard wind slabs in exposed terrain. I would expect the new snow to be quite reactive, especially where it overlies the surface hoar which was buried on March 9th. This interface is likely to be one to watch as the overlying slab develops.The mid snowpack layers are generally well settled and strong. Facets at the base of the snowpack may resurface as a concern now that spring warming is on the doorstep and full-depth releases are becoming more likely (primarily in the northern part of the region).

Problems

Wind Slabs

An icon showing Wind Slabs
Light snow and strong winds have created new wind slabs in exposed terrain. Wind slabs may be particularly reactive in areas where they overlie a weak layer of buried surface hoar.
Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>Choose well supported terrain without convexities.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Valid until: Mar 12th, 2013 2:00PM

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