Avalanche Forecast

Issued: Apr 24th, 2014 4:37PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Storm Slabs, Loose Wet and Deep Persistent Slabs.

rupert wedgwood, Parks Canada

Jasper.

Wet loose avalanches can be expected at lower elevations if rain arrives in the valley bottom.

Summary

Weather Forecast

Under the influence of a Westerly flow, the daytime freezing level will extend to 2,000 m with up to 10 cm of snow above and rain below. Overnight temperatures will drop below freezing above 1,500 m.

Snowpack Summary

A rain crust can be found from the valley bottom to 2,350m. New snow wind slabs from 2,000m extended into the alpine. Moist and wet snow can be found below the crust extending into the alpine on solar aspects. On Northerly slopes the midpack is solid but warming up. New snow clings to steep rocks above 2,350m above which are large cornices.

Avalanche Summary

Avalanche control on the 23rd produced size 1-2 soft slabs at 2200m sliding on a rain crust. At that time two cornice failures producing size 3's on steep unskiable terrain (Cromwell and Boundary peak). On the 24th, under mostly cloudy skies , several wet point release avalanches from steep rocky SW facing alpine terrain were observed.

Confidence

Freezing levels are uncertain on Friday

Problems

Storm Slabs

With increased snowfall forecasted, this slab avalanche condition will likely build. Critical loading volumes may be reached in the alpine while at its lower elevation range, rain may act as a trigger.

The new snow will require several days to settle and stabilize.Avoid convexities or areas with a thin or variable snowpack.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

On the 24th the new snow, found only at higher elevations on steep rocks, was being melted by brief moments of solar radiation. This condition will rapidly reestablish from the valley bottom to treeline with warm temperatures and rain.

Start and finish early before the surface crusts melt.Make your travel plans to take advantage of overnight freezing.

Aspects: North, North East.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

This condition seems most active on, but not exclusive to, Easterly facing slopes. Shallow rocky spots in the snowpack are likely trigger areas.

Be aware of thin areas that may propogate to deeper instabilites.Minimize overhead exposure during periods of heavy loading from new snow, wind.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Apr 25th, 2014 4:37PM