Avalanche Forecast

Issued: Apr 2nd, 2016 8:00AM

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

andrew jones, Parks Canada

Glacier.

Warm weather avalanche problems like cornices and loose wet slides will remain front and center until we get a real overnight refreeze.

Summary

Weather Forecast

Although the morning started off clear and sunny, cloud is forecast to move in today. Freezing levels rise to 2400m this afternoon with an alpine high of 3. Temperatures are poised to remain high until Monday when we will see an overnight refreeze and a return to "classic" spring conditions.

Snowpack Summary

Temperatures remained above freezing last night at treeline and in the alpine. At treeline the top meter of snow is isothermal and moist. Surface crusts forming overnight are weak and break down quickly. Multiple crusts in the top meter of the snowpack provide sliding surfaces. Dry snow exists on steep N aspects in the high Alpine.

Avalanche Summary

Large loose wet avalanches continued to be observed, triggered by strong solar input during the heat of the day. Artillery avalanche control produced 2 large loose wet avalanches on solar aspects, running well into the run-out zones of their paths.

Confidence

Problems

Loose Wet

A weak temperature inversion last night prevented the moist surface snow from refreezing. The upper snowpack will destabilize quickly with daytime warming. If the sun continues to shine today, southern aspects will be particularity vulnerable.

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.Watch for clues, like sluffing off of cliffs, that the snowpack is warming up.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Cornices

Very warm temperatures may weaken large cornices that exist along many ridges. Sagging cornices may have thinly-bridged cracks to windward which pose a serious hazard. Cornice failures can trigger deeply buried weak layers leading to large slides.

Extra caution needed around cornices with current conditions.Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

2 - 3

Persistent Slabs

Warm temps could wake up deeply buried weak layers. Recent tests on these crusts indicate that they will likely take a heavy trigger like a cornice fall or another avalanche, but if triggered very large avalanches are possible.

Use extra caution on slopes if the snow is moist or wet.Choose well supported terrain without convexities.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Apr 3rd, 2016 8:00AM