Avalanche Forecast

Issued: Apr 16th, 2016 8:40AM

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, Cornices and Wet Slabs.

Avalanche Canada istorm, Avalanche Canada

Spring Conditions: The heat is on! You need to get out super early, plan to be out of avalanche terrain no later than lunch time, and avoid being on or under weak mushy slopes.

Summary

Weather Forecast

High Pressure will clear out the clouds and warm the temperatures which could remain well above freezing at all elevations for the foreseeable future. SUNDAY: Some high cloud, freezing level rising to around 3500 m by the afternoon, no significant precipitation, light to moderate south wind. MONDAY & Tuesday: Clear and sunny, freezing level near 3500 m all day, no precipitation, light wind. Overnight temperatures may stay above freezing or the freeze could be short-lived.

Avalanche Summary

On Wednesday small storm and wind slabs to size 1.5 were reported running on a variety of aspects. On Tuesday, explosive control work near Whistler produced several size 2 cornice triggered avalanches.

Snowpack Summary

Cornices remain a concern, in part because of the potential to trigger wet slab avalanches that run to valley bottoms. Monitoring the overnight freeze of the snow surface is very important. If the snow surface does not freeze overnight or if the crust is only a few cm thick, the effect of daytime heating and solar radiation will weaken the snowpack much more quickly than it would if there is a well frozen thick crust. This is because the crust must first melt before the sun can weaken the snowpack. With the warmest weather this year forecast, layers in the mid snowpack and near the ground have the potential to wake up and become active. While isolated and unlikely, avalanches would be very large. Glide cracks are widespread, active, and best avoided. Low elevation and thin snowpack areas have 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, especially on steep, rocky faces.

Problems

Loose Wet

An icon showing Loose Wet
Rising temperatures and sunshine will likely initiate a fresh round of loose wet activity as storm snow from earlier this week looses cohesion.
Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Start and finish early before the surface crusts melt.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Cornices

An icon showing Cornices
If the sun is shining, cornices present a significant hazard. Even if they don't trigger a slab avalanche when they fall onto a slope, they have a nasty habit of running surprisingly long distances.
Pay attention to overhead hazards like cornices.>Cornices become weak with daytime heating. >

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Wet Slabs

An icon showing Wet Slabs
Warmest temperatures of the year to date and little to no overnight recovery this weekend will increase the potential for deep wet slab release.
Travel early before the heat of the day, and avoid big slopes in the afternoon.>Avoid rocky, shallow or steep slopes during the heat of the day.>Avoid sun exposed slopes, especially where the snow is wet, weak, and mushy.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Valid until: Apr 17th, 2016 2:00PM

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