Avalanche Forecast

Issued: Apr 8th, 2015 8:00AM

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

danyelle magnan, Parks Canada

Glacier.

We are in for a few more beautiful spring days. Keep in mind that conditions and hazard will vary throughout the day with aspect and elevation; warm temps and strong solar are the big factors. Be increasingly cautious as things warm up.

Summary

Weather Forecast

Warm sunny days followed by cool crisp nights are putting us into a melt freeze cycle. Today expect lots of sun with alpine temps of 0'C, freezing levels rising to 2000m and light winds. Overnight temps should drop to -10'C. Thursday temps will reach 2'C with freezing levels to 2100m. On Friday a front will bring wet flurries and gusting SW winds.

Snowpack Summary

Melt freeze cycle below 2300m is forming a strong 20cm thick crust. In the top meter of the snowpack there are multiple crusts that are reactive to tests but would likely need a large trigger. Dry snow can still be found above 2300m on shaded aspects. Isolated pockets of reactive windslab exist at ridgecrest.

Avalanche Summary

On Monday there was a skier triggered avalanche at the top of the Forever Young couloir. A thin windslab was triggered at the top resulting in a size 2.0 that ran 400m. Yesterday there were a few natural solar triggered loose wet avalanches to size 2.5. Cornice failures have also been triggering slabs in isolated locations to size 2.0

Confidence

Problems

Cornices

Warm afternoon temps and lots of solar will weaken the large cornices that exist in many areas. Recently, cornice failures have been the primary trigger of slab avalanches.

Cornices become weak with daytime heating, so travel early on exposed slopes.Stay well to the windward side of corniced ridges.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Loose Wet

Moistening snow and signs of loose avalanches pouring off cliffs are indications that the upper snowpack is weakening. When the surface is warming up it's time to minimize your exposure to slopes in the sun.

Minimize exposure to sun exposed slopes when the solar radiation is strong.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

Weak layers in the top meter of the snowpack may become more reactive as the snowpack warms with daytime heat. Large triggers like cornice falls may also cause avalanches to fail on these layers.

Caution around convexities or areas with a thin or variable snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Apr 9th, 2015 8:00AM