Avalanche Forecast

Issued: Mar 21st, 2016 10:22AM

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

jlammers, Avalanche Canada

Northwest Coastal.

Conditions may change quickly in the spring. Even brief periods of sun can trigger pushy loose wet avalanches or promote destructive cornice falls.

Summary

Confidence

High

Weather Forecast

On Tuesday expect generally overcast skies with isolated flurries. On Wednesday a Pacific system will bring 5-15cm of new snow to the region. Light flurries are forecast for Thursday. Ridgetop winds will be light on Tuesday, and then become moderate and southeasterly with Wednesday's precipitation. Freezing levels should hover between 1100 and 1200m for the forecast period.

Avalanche Summary

No recent avalanches have been reported.

Snowpack Summary

Light amounts of new snow have been shifted by strong southeast winds into wind slabs in exposed high elevation terrain while settled powder can be found on shaded and sheltered slopes. Spring conditions have continued to develop. With that, lower elevation and sun-exposed slopes will likely appear moist or refrozen. A layer of surface hoar or melt-freeze crust buried on March 3 is down 50-80cm and has been on the radar of professionals in the mountains north of Stewart. A more widespread crust/facet layer buried in early February can now be found down over a meter. Both of these deeper layers have become less likely to trigger, but have the potential for large avalanches especially with a large trigger such as a cornice fall. I'd be increasingly cautious during periods of warming or solar radiation.

Problems

Cornices

Natural cornice releases remain an ongoing concern for professionals in the region. During the past week, falling cornices have also triggered large avalanches on the slope below.

Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 5

Wind Slabs

Strong southeast winds have formed hard and potentially reactive wind slabs in high elevation lee terrain. Brief periods of sunny weather may also promote loose wet avalanche activity on sun-exposed slopes

Be cautious as you transition into wind affected terrain. >Be aware of the potential for wide propagations due to the presence of hard windslabs.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

A few persistent weaknesses exist in the mid snowpack (see snowpack description). These potentially destructive layers may become reactive with spring warming or with a large trigger such as a cornice fall.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar. >Conditions have improved, but be mindful that persistent instabilities are still present.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Mar 22nd, 2016 2:00PM