Avalanche Forecast

Issued: Feb 23rd, 2013 8:10AM

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

Catherine Brown, Parks Canada

Glacier.

Choosing conservative terrain today will bring you to good skiing in the park. Be on the lookout for any signs of a weak snowpack... recent avalanches, settlements or cracking around skis.

Summary

Weather Forecast

Light snow today with moderate/heavy snow forecast for tomorrow. Winds will be light to moderate from the west/northwest. Expect alpine temperatures around -7 today. Light snow is expected to continue on Monday with freezing levels around 800m.

Snowpack Summary

30 cm of storm snow has fallen in 2 days. Storm slabs are present on lee features at treeline and in alpine from moderate southerly winds. Below treeline the new snow is unconsolidated. A surface hoar layer, buried on Feb 12, is down 50-70cm. This layer has been most reactive between 17-1900m and where it sits on a sun crust.

Avalanche Summary

A skier triggered a size 2 avalanche yesterday, 1700m, SE aspect down 35-45cm on surface hoar sitting on a 2-3cm crust. See image here. We observed a small natural avalanche cycle mid-day yesterday. Avalanches sized 1.5-2.5 were running in the storm snow. None of these avalanche triggered deeper layers.

Confidence

Intensity of incoming weather systems is uncertain on Sunday

Problems

Storm Slabs

New snow has created touchy conditions. Skiers could trigger avalanches today. Use caution in steep terrain. Watch for slab formation where wind has deposited firmer snow. Cracking around skis is a clue slabby conditions are present.

Choose conservative lines and watch for clues of instability.The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

A weak layer is down 50-70cm. It is most likely to be skier-triggered around 17-1900m, avoid open slopes and convex rolls. On sunny aspects the weak layer can be touchy. See image of skier-triggered avalanche yesterday on this layer at 1700m.

Avoid runouts where triggering slopes from below is possible.Dig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Feb 24th, 2013 8:00AM