Avalanche Forecast

Issued: Apr 9th, 2013 4:27PM

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

a.l. horton, Parks Canada

Jasper.

A spring storm on Wednesday will bring strong westerly winds, rain at lower elevations and up to 25 cm above 2000 m.

Summary

Weather Forecast

Expecting 10 to 15 mm of precipitation on Wednesday. This will fall as rain at lower elevations and may translate to over 25 cm of snow at and above treeline. Strong westerly winds will accompany this precipitation and temperatures will remain cool for this time of year.

Snowpack Summary

Rain will weaken the melt freeze crust below treeline producing a wet and unconsolidated snowpack. Windslabs will build on the smooth temperature crusts at and above treeline on north to east aspects.

Avalanche Summary

No avalanche activity has been reported or observed in the past 5 days.

Confidence

Timing, track, or intensity of incoming weather system is uncertain on Wednesday

Problems

Storm Slabs

Up to 25 cm of storm snow accompanied by strong SW winds will build slab conditions on the smooth sliding surface formed by previous temperature crusts on lee treeline and alpine slopes.

Minimize exposure during periods of heavy loading from new snow, wind.The new snow will require several days to settle and stabilize.

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

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 3

Loose Wet

10-15 mm of rain on Wednesday will destabilize the melt freeze crust currently covering the isothermal snow below. Expect loose wet slides on steeper slopes and in gulley features.

Be very cautious with gully features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Cornices

Cornices are big and will continue to build with the forecasted weather. Minimize your exposure time beneath them and staying well back from wind exposed ridge crests.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Apr 10th, 2013 4:00PM