Avalanche Forecast

Issued: Feb 24th, 2015 9:02AM

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

ghelgeson, Avalanche Canada

South Rockies.

Forecast snowfall amounts for Tuesday night range from 0 to 15cm. If snow totals actually approach 15 cm, the danger rating will likely increase one level at all elevations.

Summary

Confidence

Poor - Forecast snowfall amounts are uncertain on Tuesday

Weather Forecast

Tuesday Night: 0 to 15cm possible, freezing level 1500m, winds moderate to strong NW. Wednesday: Increasing cloud cover, winds decreasing to light NW by sundown. No precipitation, freezing level at valley bottom. Thursday: Broken skies, light variable winds at all elevations, no significant precipitation, freezing level at valley bottom. Friday: Broken skies, light variable winds at all elevations, no significant precipitation, freezing level at valley bottom.

Avalanche Summary

No new avalanches have been reported recently.

Snowpack Summary

10 to 15cm of old storm snow rests upon a thick supportive crust that extends up to 2100m before changing to a firm wind pressed surface at higher elevations. Winds were out of the NE over the weekend switching to the NW over the last few days. You can likely find thin wind slabs at upper elevations as a result. Below 2100m the crust is effectively capping the snowpack, keeping riders from interacting with deeper weak layers that exist in the snowpack. Two layers of surface hoar can be found down between 50 and 80cm. Recent snow pack test indicate that these layers are unlikely to fail but could propagate widely if they do. At upper elevations where these layers are not protected by the surface crust it may still be possible to trigger an avalanche from a thin or rocky spot. The mid-December crust is becoming harder to find but where it does exist (mainly at treeline elevations) it is over a meter down.

Problems

Storm Slabs

0 to 15cm of snow is expected Tuesday night. Any snow that falls will likely be formed into thin sensitive wind slabs by strong NW winds.

Fresh wind slabs may hide older wind slabs.>If snow totals begin to stack up, there will likely be some power sluffing in bigger terrain. >

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

Large avalanches are unlikely in most places but may be possible in the high alpine where a large trigger in a thin rocky spot could cause an avalanche on a buried persistent week layer.

Be aware of the potential for very large, deep avalanches due to the presence of buried surface hoar or a facet/crust layer.>Be alert to conditions that change with elevation, the surface crust that is protecting deeper weak layers tapers out in the high alpine.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Feb 25th, 2015 2:00PM