Avalanche Forecast

Issued: Apr 26th, 2017 8:03AM

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

percy woods, Parks Canada

Glacier.

Summary

Weather Forecast

Mainly cloudy with isolated flurries and a chance of an afternoon thunderstorm.. Alpine high of -3C, light ridgetop winds and a freezing level edging up to 1800m. Thursday there is snow to 5cm in the alpine forecast with a freezing level of 1700m.

Snowpack Summary

High elevation N aspects still hold a winter snowpack with surface windslab that may be sensitive to human triggering given the right location. On solar aspects expect temp crusts and sun crusts in morning and moist surface as the day warms. Field trip yesterday showed little recovery in surface crusts until 1900m. Unsupportive snow below 1700m.

Avalanche Summary

Recent slab releases off of lower slopes of Sir Donald to size 3. Numerous point releases from the past week at below treeline elevations. There were human triggered slides on alpine N aspects to size 2 on Sunday.

Confidence

Problems

Wind Slabs

Expect to find pockets of windslab on high elevation N aspects formed by recent S-SW winds. Skiers reported triggering windslab to size 2 on Sunday.

Watch for whumpfing, hollow sounds, and shooting cracks.Use caution in lee areas. Recent wind loading has created wind slabs.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Loose Wet

Poor overnight crust recovery at low elevations last night. Surface crust breakdown can be expected with daytime warming. Wet slides may occur later in the day.

Use extra caution on solar slopes or if the snow is moist or wet.Avoid terrain traps, such as gullies, where the consequences of a small avalanche could be serious.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Cornices

Cornices are huge and hanging over alpine lee slopes in many places. Daytime warming may promote failure of these large triggers. Cornice failure may wake persistent weak layers.

Pay attention to overhead hazards like cornices which could trigger slabs.Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Apr 27th, 2017 8:00AM