Avalanche Forecast

Issued: Feb 25th, 2013 10:15AM

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

jlammers, Avalanche Canada

Purcells.

Significant snowpack and weather variations exist throughout the region. Be aware of conditions that are specific to your area and make observations continuously as you travel.

Summary

Confidence

Poor - Due to variable snowpack conditions

Weather Forecast

Tuesday: Light snowfall / Light northwest wind / Freezing level at 1000mWednesday: Light snowfall / Light west winds / Freezing level at 1000mThursday: Light snowfall /Â Moderate south winds / Freezing level at 1000m

Avalanche Summary

Slab avalanches to size 1.5 were ski cut in the region on Sunday. These releases failed within the recent storm snow. In general, observations were limited..

Snowpack Summary

Light to locally moderate amounts of new snow have fallen adding to an ongoing storm snow instability, particularly on the west side of the region where accumulations have been highest. The new snow is most likely reactive as a wind slabÂ in exposed terrain or as loose snow in sheltered areas.Â The variably reactive February 12th and 15th surface hoar layers now exist up to 80cm below the surface and seem most prevalent on the west side of the region. This interface may also be reactive on solar aspects where a sun crust exists. A surface hoar layer buried on February 23 is still on the radar of some operators. This layer has been less likely to trigger by skiers, but may still be sensitive to large loads like avalanches in motion or cornice fall. The mid and lower snowpack are generally well settled and strong.

Problems

Storm Slabs

Where higher recent accumulations exist, triggering storm slabs may be likely, especially in wind-affected areas. In sheltered terrain the new snow may react as a loose dry avalanche.

Be cautious as you transition into wind affected terrain.>Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be cautious of sluffing in steep terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

Loading from new snow and wind may add reactivity to persistent buried surface hoar layers. In deeper snowfall areas, resulting avalanches may be large.

Dig down to find and test weak layers before committing to a line.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Feb 26th, 2013 2:00PM