Avalanche Forecast

Issued: Apr 1st, 2015 9:00AM

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

ccampbell, Avalanche Canada

Northwest Coastal.

A weak surface hoar layer is creating touchy conditions in some areas. If you have field observations to share, please consider using the Mountain Information Network. Click here for more info.

Summary

Confidence

Good

Weather Forecast

5-15cm of snow falling under moderate southeasterly winds is expected throughout the day Thursday with an additional 5-15 cm by Friday morning. Unsettled conditions are expected for Friday and Saturday with 5-10 cm possible each day. Daytime high freezing levels should hover around 1300 m for the forecast period.

Avalanche Summary

Reports from Tuesday include several explosive-controlled wind slab avalanches up to Size 2. In the northern part of the region numerous skier-triggered slabs up to Size 2, including wide propagations and remote triggers, have been associated with a surface hoar weak layer buried on March 25th.

Snowpack Summary

Another 10-20 cm brings recent settled storm snow totals up to 50 cm overlying a variety of old snow surfaces including surface hoar. There is some uncertainty regarding the distribution of this buried surface hoar layer, although touchy conditions are being reported in the north of the region. Strong winds have significantly redistributed the storm snow into deep wind slabs on northwest through northeast aspects.

Problems

Persistent Slabs

A weak surface hoar layer has recently produced large remotely triggered avalanches, and is now buried by up to 75cm of snow. We're still getting a handle on the distribution of this layer. Until we do, I'd assume it's in most parts of the region.

Dig down to find and test weak layers before committing to a line.>Be aware of the potential for large avalanches due to the presence of buried surface hoar.>Choose conservative lines and watch for clues of instability.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Storm Slabs

Recently formed storm slabs should gradually gain strength over the next few days. That said, large avalanches are still possible in in higher elevation, wind-exposed terrain.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be alert to conditions that change with aspect and elevation.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Apr 2nd, 2015 2:00PM