Avalanche Forecast

Issued: Mar 15th, 2019 3:00PM

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

mike.koppang, Alberta Parks

Kananaskis.

Freezing levels and solar radiation are key elements to be aware of. This will be the first pulse of heat to a weak snowpack this weekend so watch temps, freezing levels, aspects and cloud cover.

Summary

Confidence

Moderate -

Weather Forecast

Temperatures on Saturday are forecast to be more spring like with freezing levels climbing to 2000m by mid afternoon. No new precip is forecast and winds are forecast to calm down into the light to moderate range out of the SW. The big thing to pay attention to will be the solar radiation. Strong solar input will quickly decrease stability on solar aspects especially in steep thin rocky terrain.

Avalanche Summary

Numerous loose dry avalanches up to sz 1.5 were observed on Friday. Field teams were in before the temperatures really warmed up so there also may have been a few loose wet on steep solar aspects later in the day.

Snowpack Summary

10-15cm of snow fell (drainage dependant) through convective flurries over the past 24hrs. This snow tapers to only a few cms at lower elevations. The previous warm temps have created widespread temperature crusts on solar aspects up to 3000m. Windslabs from the moderate SW winds on Friday are evident in alpine terrain up to 20cm thick. These slabs are overlying the previous facetted surface and if they initiate, they are quick to entrain the weak lower snowpack and run far. Watch for these wind slabs overlying this weak facetted base and also be aware of awakening the lower down basal facets from a thin weak area.

Problems

Wind Slabs

New winsdlabs are being found in Alpine terrain and isolated areas at TL up to 20cm thick.

Be careful with wind loaded pockets while approaching and climbing ice routes.Caution in lee and cross-loaded terrain near ridge crests.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

This layer is still concerning and could be woken up by a skier/rider in a thin shallow snowpack area, warmer temps with some solar radiation or a cornice failure. This problem deserves respect as any resulting avalanche will be full depth.

Be aware of the potential for wide propagations due to the presence of hard windslabs.Be aware of the potential for full depth avalanches due to deeply buried weak layers.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Loose Dry

Watch for loose dry slides from steep unskiable terrain. If/When the sun comes out these may also initiate more readily on solar aspects as loose dry and/or loose wet.

If triggered the loose wet sluffs may step down to deeper layers resulting in large avalanches.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Likely - Very Likely

Expected Size

1 - 1.5

Valid until: Mar 16th, 2019 2:00PM