Avalanche Forecast

Issued: Feb 18th, 2015 8:00AM

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

danyelle magnan, Parks Canada

Glacier.

Summary

Weather Forecast

The ridge of high pressure will mean another mostly sunny day today, with an alpine inversion. Expect a high of -1 with moderate SW winds at ridgetop. Overnight, a cold front will approach from the coast. Thrusday will be cloudy with flurries. Temps will range from -10 to -5 with gusty westerly winds. Friday will be mostly cloudy with flurries.

Snowpack Summary

Above 1700m 5-15cm of light snow sits on the Feb 14 crust, which is supportive to ~1900m. The Jan 30 crust layer is down ~1-1.25m is becoming more stubborn to trigger. Jan 15 surface hoar down ~1-1.5m gives sudden test results in isolated areas. The mid and lower snowpack is well settled. Nov 9 basal crust layer still present in the alpine.

Avalanche Summary

Solar triggered avalanches have been observed for the past 2 days to size 2.5. On the weekend, impressive deep slab avalanches occurred. A size 3.5 from the col between Clarke Peak and Mt Swanzy was likely triggered by cornice fall and ran on glacier ice. In the Asulkan Valley, a size 3.0 from Mt Pollux ran on the Nov 9 crust/to ground.

Confidence

Problems

Cornices

Impressive avalanches have been triggered recently by cornices falling on slopes, some failing to deep basal layers. Minimize exposure to slopes with cornices above even if you are in the shade, as the cornices above are still in the sun.

Cornices become weak with daytime heating. Pay attention to overhead hazards like cornices.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 4

Loose Wet

5-15cm of snow over a firm surface can be released as loose avalanches with solar effect. Solar radiation today will be strong with clear skies.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

Persistent weak layers down ~1 to 1.5m will likely need a large load such as a cornice failure to be triggered. A light load, like you, may be able to trigger them from shallow areas. If triggered these layers continue to propagate widely.

Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

3 - 4

Valid until: Feb 19th, 2015 8:00AM