Avalanche Forecast

Issued: Mar 10th, 2015 9:30AM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

The snowpack is in transition to Spring conditions, but it is not there yet. Danger levels will rise on solar aspects with solar radiation and daytime heating. A poor freeze is expected Wednesday night. Ski quality remains poor in most areas.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

A mix of sun and cloud for Wednesday with strong winds from the west. Temperatures will be mild with freezing levels rising to 2200m. Very light precipitation is possible on Thursday under a mix of sun and cloud and mild temperatures.

Avalanche Summary

A size 2.5 slab avalanche occurred in the past 24 to 48 hours on a steep south-west aspect at 2700m on Snow Peak. The avalanche was a wind slab, but it is suspected to have been triggered by solar radiation in the shallow snowpack start zone. Several loose wet avalanches up to size 2.0 have also occurred on steep south, south-west and west aspects in the past 2 days.

Snowpack Summary

Widespread wind effect in the alpine and open areas at treeline. These areas exhibit hard wind slab, soft wind slab, sastrugi, breakable wind crust and everything in between. Solar aspects were moist to 2600m, but sheltered polar aspects stayed dry all dry. The November facets/depth hoar combo persists and has been responsible for a couple of recent natural and human triggered slides.

Problems

Wind Slabs

Wind slabs have become more reactive in steep terrain over the last few day. Both human and naturally triggered slides have occurred.

Caution in lee and cross-loaded terrain near ridge crests.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Loose Wet

Daytime heating and solar radiation is causing loose wet slides up to size 2.0 on steep solar aspects. Shallow snowpack areas and rocky terrain is more quick to heat up and destabilize.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Avoid exposure to solar aspects overhead, large avalanches may reach the end of run out zones.>

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

The basal weak layers ares still a concern in steep alpine terrain, especially in shallow snowpack areas. Large triggers, such as cornices, may also be enough to wake up this deep persistent weak layer.

Cornices become weak with daytime heating, so travel early on exposed slopes.>Be aware of thin areas that may propogate to deeper instabilites.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Mar 11th, 2015 2:00PM