Avalanche Forecast

Issued: Apr 20th, 2015 4:00PM

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

mike eder, Parks Canada

Jasper.

Plan your trip to avoid overhead cornice hazards and finish early.

Summary

Weather Forecast

Tuesday will bring sun and warm temperatures. Freezing level will rise to 2700m or higher by noon and stay there for most of the day. The weather models conflict for Wednesday's precipitation amount yet we remain hopeful. Temperatures will drop and the skies will be overcast.

Snowpack Summary

Pockets of wind slab are present in the upper alpine from previous strong winds last week yet largely unreactive. At treeline, lee aspects have a series of windslabs sandwiched with thin weaknesses in the upper snowpack. A strong midpack bridges over weak basal facets on Northerly aspects at treeline and above.

Avalanche Summary

Cornice failures to size 2.5 have occurred around the Icefields area on North to East aspects. They did not initiate a slab on the slopes below. Intense solar radiation will likely increase the cornice falls and initiate afternoon wet loose avalanche conditions on Tuesday.

Confidence

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

Problems

Cornices

Cornices are large and will respond to Tuesday's warm temperatures. Stay well back from the edge while traveling along ridge lines. Pay attention to what is above and avoid cornice exposed slopes.

Do not travel on slopes that are exposed to cornices overhead.Give cornices a wide berth when travelling on or below ridges.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Loose Wet

As temperatures warm up so does the potential for loose wet avalanches. It may be enough to trigger deeper basal layers on steeper unsupported slopes.

Start and finish early before the surface crusts melt.Watch for terrain traps where small amounts of snow will acumulate into deep deposits.

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Apr 21st, 2015 4:00PM