Avalanche Forecast

Issued: Apr 30th, 2015 8:00AM

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, Wind Slabs and Cornices.

danyelle magnan, Parks Canada

Glacier.

Summary

Weather Forecast

Today will be mainly cloudy with scattered flurries, freezing levels to 2100m and moderate to strong SW winds. A mix of sun and cloud with isolated wet flurries. Friday will be a mix of sun and cloud with freezing levels rising to 2300m. Sat will be similar but with scattered flurries.

Snowpack Summary

There was a weak overnight recovery. The snowline lowered to ~1500m, with 6cm of new snow at 1900m. Strong winds at ridgetop were observed to be transporting snow, likely forming loaded pockets of windslab. The new snow overlies a moist and isothermal snowpack.

Avalanche Summary

Numerous loose wet avalanches, triggered by warm temps, were observed along the highway corridor. They were observed from all aspects. The average size was size 2, but there were also a few size 3's observed.

Confidence

Problems

Loose Wet

Rain early yesterday weakened the snowpack. This weak snow has now been buried by up to 10cm of new snow at higher elevations. Sunny periods may trigger loose avalanches in the new snow, which will entrain the moist snow below.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.Be increasingly cautious on sun exposed slopes.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 3

Wind Slabs

Up to 10cm of new snow was loaded onto the lees of ridgecrests yesterday by strong SW winds. This is forecast to continue today. Deeper pockets of reactive windslab are most likely to exist in the same areas as the most appealing skiing.

Use caution in lee areas. Recent wind loading have created wind slabs.Be cautious as you transition into wind affected terrain.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Cornices

Large cornices are likely becoming weaker with continued mild temps and as the weight of rain and snow are added.

Pay attention to overhead hazards like cornices.Give cornices a wide berth when travelling on or below ridges.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: May 1st, 2015 8:00AM