Avalanche Forecast

Issued: Nov 16th, 2013 8:56AM

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

danyelle magnan, Parks Canada

Glacier.

Shallow snow at lower elevations means barely hidden hazards like rocks and stumps are hard to avoid.

Summary

Weather Forecast

Mainly cloudy with flurries and light W winds are expected today. On Sunday, expected continued flurries with up to 8cm through the day. Winds will increase on Sunday, with moderate W'ly winds gusting to strong at ridgetop. Natural avalanches are likely from steep lee slopes when the winds pick up. Precipitation will taper off on Monday.

Snowpack Summary

~25cm of new snow fell yesterday with light SW winds. This unconsolidated snow will have buried windslabs that formed earlier in the week. A surface hoar layer, most prevalent around 1800m, is down ~50cm and collapses easily in tests. Skiers reported cracking in areas with windslabs. Below treeline the snowpack is thin, barely covering hazards.

Avalanche Summary

2 size 2 natural avalanches were observed yesterday off steep N facing paths on Mt Macdonald and running through the alder into the avalanche fans. Suspect more activity with new storm snow overnight, but at least the winds have tapered off for Saturday. On Sunday expect increased avalanche activity from steep lee paths as the winds pick up again.

Confidence

Due to the number of field observations

Problems

Storm Slabs

A series of storms this week dropped about 50cm at treeline. Temps have cooled off now, but cohesive storm slabs formed with warm temps earlier. These overly a buried surface hoar layer and windslabs.

Dig down to find and test weak layers before committing to a line.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Wind Slabs

Moderate to strong SW winds at ridgetop earlier this week formed windslabs on exposed slopes at treeline and above. Skiers reported cracking around their skis and pockets of windslab that were reactive to ski cuts. These windslabs are now buried.

Use caution in lee areas in the alpine. Recent wind loading have created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Nov 17th, 2013 8:00AM