Avalanche Forecast

Issued: Jan 25th, 2015 4:32PM

The alpine rating is high, the treeline rating is high, and the below treeline rating is high. Known problems include Loose Wet, Deep Persistent Slabs and Wind Slabs.

conrad janzen, Parks Canada

Banff Yoho Kootenay.

A natural avalanche cycle occurred today due to the warm temperatures. We expect this to continue until things cool down. Until then avoid all avalanche terrain and minimize your exposure to large slopes when traveling at valley bottom.

Summary

Weather Forecast

Continued warm temperatures with freezing levels near ridge tops and strong to extreme W winds continue for Monday. On Tuesday things begin to cool off slightly and we may see some light precipitation. Wednesday the cooling trend continues with winds shifting to the North and generally clear skies.

Snowpack Summary

Strong to extreme SW winds creating wind slabs in open areas above tree line and intense wind transport at ridge tops. Moist snow to ridge top on solar aspects and on all aspects below tree line. Becoming isothermal in shallow low elevation snow pack areas. Dec 18th and basal facets failing naturally and producing avalanches up size 2.5 today.

Avalanche Summary

Numerous natural avalanches were observed and reported today with slabs up to size 2.5 at tree line and above and loose wet slides up to size 2 below tree line in all of the forecast region. Notably Cascade Falls, Rogans Gully, Bourgeau L & R and many of the climbs in Field all saw avalanche activity today. We expect this cycle to continue tomorrow

Confidence

Freezing levels are uncertain on Tuesday

Problems

Loose Wet

Strong winds may keep snow surfaces cool at upper elevations, but lower elevations and thin rocky areas on solar aspects should be suspect and may trigger the weaker basal layers and subsequent larger avalanches.

Watch for clues, like sluffing off of cliffs, that the snowpack is warming up. Avoid steep, open slopes.

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Deep Persistent Slabs

In shallow snowpack areas (most of the region) the weak base of the snowpack persists and has been failing naturally in steep terrain. Although in some areas, the Dec. 18th layer persists, management of both layers should be the same.

Be aware of the potential for wide propagations.Avoid all avalanche terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

2 - 3

Wind Slabs

New wind slabs will continue to form in open areas above tree line with the strong W winds and warm temperatures. These will be prone to human triggering over the next few days.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Be careful with wind loaded pockets while approaching and climbing ice routes.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Jan 26th, 2015 4:00PM