Avalanche Forecast

Issued: Apr 22nd, 2014 6:27PM

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

garth lemke, Parks Canada

Jasper.

Maligne lake road and Icefields parkway is closed due to the rain/snow storm. Avalanche control will occur Wednesday and Thursday. Call 780-852-3311 or Alberta 511 for updates.

Summary

Weather Forecast

Tuesday evening into Wednesday is bringing heavy rain changing to snow with freezing level to valley bottom sometime overnight. Wednesday will be continued snow, 10-20cm or locally more amounts at the Icefields, and freezing level 1700m in the afternoon. Rain will continue at low elevations. A gradual cooling trend should occur into Thursday am.

Snowpack Summary

The top 20cm is moist or wet up to 2200m elevation with rain. As it changes to snow, expect a storm slab developing mainly treeline and above. It will rest on a previous temperature crust on many aspects. Alpine elevations, the snowpack has a solid mid-pack over a faceted base. Cornices are large and ominous. BTL the crust is deteriorating.

Avalanche Summary

It drizzled rain all day with building intensity towards 5pm. As a result, several size 2.5-3 wet slabs were noted late in the day, East aspects, 1900-2000m elevation, to ground, stopping mid-fan. Visibility was poor. Numerous small moist events size 1-2 were observed above 2300m.

Confidence

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

Problems

Wet Slabs

With Tuesday's precipitation, the basal facets are being overloaded with several avalanches noted running to ground up to size 3. This will likely continue through Wednesday but should be gradually regulated by cooling temperatures.

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

Storm Slabs

If significant snowfall occurs, a storm slab problem will develop. The problem may be active on Wednesday and Thursday but should be relatively short lived after few days of settlement. this storm slab is developing on slippery temperature crust.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Loose Wet

This will persist mainly at lower elevations as rain deteriorates the crust. Temperatures trending cooler should regulate the higher elevations.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 23rd, 2014 4:00PM