Avalanche Forecast

Issued: Apr 24th, 2016 8:02AM

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

jlammers, Avalanche Canada

Purcells.

Increased solar radiation over the next few days will keep the Avalanche Danger elevated.

Summary

Weather Forecast

Expect a mix of sun and cloud from Monday to Wednesday. Ridgetop winds will remain mainly light while freezing levels will climb gradually from 1900m on Monday to about 2400m by Wednesday.

Avalanche Summary

Most commercial operations have closed for the season, and data is becoming sparse. If you have any avalanche activity to report, please consider sharing through the Mountain Information Network.

Snowpack Summary

Monitoring the snow surface is very important during the spring. If the snow surface does not freeze overnight or if the crust is only a few cm thick, the effect of daytime heating, rain or solar radiation will weaken the snowpack much more quickly than it would if there is a well frozen thick crust. Deeply buried weak layers in the mid snowpack and near the ground still have the potential to wake up and become active with a rapid warm up. While unlikely, releases on these deeply buried weak layers would result in very large avalanches. Glide cracks are widespread, active, and best avoided. Cornices are large, fragile, and could trigger deep slab avalanches that run to valley bottoms. The snowpack in many areas has become isothermal, meaning the snowpack is 0 degrees Celsius throughout. An isothermal snowpack is more prone to full depth wet slab avalanches during the heat of the day.

Problems

Loose Wet

Rain and then sun will promote ongoing loose wet avalanche activity. Areas of greatest concern are steep gullies and faces on sun-exposed slopes. New snow that is exposed to sunlight for the first time will be especially reactive.

Watch for surface clues such as sluffing off of cliffs and pinwheeling. These are red flags that should prompt you to reevaluate the conditions. >

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Wet Slabs

Destructive wet slab avalanches should still be on your radar, especially with forecast solar radiation. Wet slabs may fail on layers in the mid snowpack, or at the ground.

Avoid slopes with glide cracks. >Be aware of the potential for large, deep avalanches. >

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 6

Cornices

Use extra caution when traveling on corniced ridges. Despite the slight cooling trend, cornices will remain sensitive to human triggering.

Stay well back from cornices. >Cornice releases have the potential to trigger deeply buried weak layers. >Pay attention to overhead hazards like cornices. >

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 5

Valid until: Apr 25th, 2016 2:00PM