Avalanche Forecast

Issued: Mar 29th, 2016 8:25AM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

Start early and finish early. Intense solar radiation and very warm temperatures will lead to an increase in hazard levels, possibly reaching HIGH. In addition to the problems discussed below, cornices and their underlying slopes should be avoided.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

Wednesday should be cloudy with sunny periods and isolated wet flurries (possibly rain). Freezing levels will climb to 2600m. Alpine temperatures are expected to reach a high of 2 C.Â Ridge-top winds will be out of the north at 20 km/h gusting to 50 km/h.

Avalanche Summary

Several loose wet avalanches up to size 2.0 were observed today in steep alpine terrain on solar aspects. Many of these initiated from shallow rocky areas.

Snowpack Summary

The snowpack is settling under the influence of intense solar radiation and daytime heating. Moist snow observed today on all solar aspects up to mountain top and on northerly aspects up to 2200m. Numerous buried crusts are found on all but sheltered north aspects, and many of these crusts are producing shears in snowpack stability tests in the easy to moderate range. We are also observing consistent shears in the hard range deep in the snowpack on the Jan 6th interface down between 100 and 130cm. The basal layers consist of large depth hoar and facets. Slabs up to 50cm thick are still found in lee and cross-loaded features in the Alpine. Much of the region has a snowpack with a dense mid-pack overlying very weak basal layers which indicates the potential for full depth avalanches, triggered either from a large load (such as a cornice) or from a step-down from an avalanche initiated in the upper snowpack. The snowpack is not yet in typical "spring condition", though it is evolving that way.

Problems

Persistent Slabs

Slabs averaging 50cm thick are still found in lee and cross-loaded terrain in the Alpine. If triggered, these could step down to a deeper layer. There is also concern on solar aspects for a slab to fail on one of the numerous buried crust interfaces.

Avoid steep, open slopes.>Avoid lee and cross-loaded terrain near ridge crests.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Loose Wet

Intense solar radiation and warm temperatures will lead to loose wet avalanches beginning on SE slopes in the morning and moving to S and W aspects through the day.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Watch for clues, like sluffing off of cliffs, that the snowpack is warming up. >

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Deep Persistent Slabs

The current snowpack structure of dense mid-pack overlying as much as 80cm of weak facets is a recipe for full depth avalanches. Triggering from shallow snowpack areas is a particular concern.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Avoid exposure to solar aspects overhead, large avalanches may reach the end of run out zones.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Mar 30th, 2016 2:00PM