Avalanche Forecast

Issued: Apr 21st, 2014 4:00PM

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

garth lemke, Parks Canada

Jasper.

Monitor the expected storm arrival and freezing levels Tuesday afternoon. Rain can tip the scales quickly.

Summary

Weather Forecast

Flurries Monday night with less overnight freeze than previous. Tuesday will bring a storm in the afternoon, freezing levels 2000m or higher, and SE winds. Models are not agreeing as to precipitation amounts Tuesday and Wednesday but expect rain below 2000m. The storm may be more intense around the Icefields and Saskatchewan crossing.

Snowpack Summary

The crust remains intact except for the steepest solar facing aspects below tree-line. The snowpack remains moist below this crust. Higher elevations, the snowpack has a solid mid-pack over a faceted base. Cornices are large and ominous. Watch for a storm slab problem developing on Wednesday with this current surface crust being a weak interface.

Avalanche Summary

One size 1 isothermal slide noted along Maligne lake road at 1500m elevation. No new avalanches noted in the Icefields area.

Confidence

Freezing levels are uncertain on Tuesday

Problems

Loose Wet

Overnight recovery of the melt freeze crust is occurring but less so every day. Expect loose wet slides by mid-day especially if the day is warm and rain occurs. Gauge the amount of overnight freeze as to how quickly it can destabilize.

Start and finish early before the surface crusts melt.Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

No recent activity on this layer; however, triggering remains possible from thin rocky areas on loaded features.

Be aware of thin areas that may propogate to deeper instabilites.Avoid convexities or areas with a thin or variable snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Apr 22nd, 2014 4:00PM