Avalanche Forecast

Issued: Nov 26th, 2014 8:07AM

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

danyelle magnan, Parks Canada

Glacier.

Avalanche danger will increase as the forecast storm hits us. If freezing levels rise, danger will rise rapidly. Stick to low angled slopes and avoid overhead exposure.

Summary

Weather Forecast

A warm front will bring warm temperatures and moderate to heavy precipitation today and tomorrow. Up to 20cm of new snow is expected by Thursday morning and another 15-25 cm on Thursday. It is possible that freezing levels will spike today, potentially resulting in rain up to treeline. Moderate SW winds will increase loading.

Snowpack Summary

Two layers of concern, the Nov 21 surface hoar/sun crust layer down ~75 and Nov 9 rain crust down ~100cm, are becoming reactive as the load on top of them increases. Snowpack tests in two locations, a south aspect and a north aspect, showed that these layers may be triggered by skiers and if triggered are likely to propagate into large avalanches.

Avalanche Summary

Numerous natural avalanches were observed yesterday. Up the Connaught drainage avalanches to size 2.5 were observed from the paths off of Mt Cheops. Cheops North bowl ran into the creek. Along the highway avalanches were observed from all aspects running well into the avalanche run-out zones. Most were size 2, but there were two size 3's.

Confidence

Track of incoming weather systems is uncertain

Problems

Storm Slabs

Continued snowfall is adding to the storm slab sitting on touchy layers. There continue to be reports of whumphing and tests yesterday confirm these layers can be triggered by skiers. These will become increasingly reactive as the load increases.

Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Loose Dry

Loose avalanches are possible on steep sheltered slopes and gullies. Be cautious in these areas, where a bit of sluffing snow can quickly gain mass.

Watch for terrain traps where small amounts of snow will acumulate into deep deposits.Be aware of party members below you that may be exposed to your sluffs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Wind Slabs

Recent and forecast winds from the south will load lee slopes and form cohesive slabs. Wind loading will also trigger natural avalanches. Avoid exposure to steep paths that are being rapidly loaded, such as the Cheops North paths.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.Avoid avalanche terrain during periods of heavy loading from new snow and wind.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Nov 27th, 2014 8:00AM