Avalanche Forecast

Issued: Apr 18th, 2014 4:00PM

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

a.l. horton, Parks Canada

Jasper.

Daytime heating and direct solar exposure will rapidly increase the avalanche danger. Plan to be off slopes if moist or wet snow conditions are encountered. Avalanche control planned on Hwy 93 between Parkers and Weeping Wall late Saturday PM.

Summary

Weather Forecast

Rain/snow showers to continue this evening and then skies will clear overnight bringing cool temps that will likely develop a crust from treeline to valley bottom. Mostly clear skies Saturday with warming temperatures. Similar conditions expect through Monday however overnight temperatures may not be cold enough to develop a significant crust.

Snowpack Summary

Temps peaked well above freezing Friday PM reaching into the alpine. This will create a crust on most aspects to treeline (TL) on solar aspects in the alpine as temps cool overnight. Moist snow below the crust extends into TL. The mid-pack is well bonded and warm. The base is weak facets in most locations. Cornices are large.

Avalanche Summary

2 new sz 2 slab avalanches ~ 50 - 100 cm deep where observed on SW TL aspect in the Icefields area, these went on an old snow interface, likely the Feb 10th layer. Several loose dry releases produced avalanches to sz 1.5 out of steep alpine terrain on SW aspects. Numerous small loose wet avalanches were reported on all aspects to treeline.

Confidence

Freezing levels are uncertain on Saturday

Problems

Loose Wet

Daytime heating and direct solar radiation will deteriorate the crust by mid afternoon and avalanches are likely after this time. Steep solar aspects have the greatest likelihood.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

Shallow rocky areas are likely trigger spots on steeper loaded terrain features.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Apr 19th, 2014 4:00PM