Avalanche Forecast

Issued: Jan 23rd, 2016 8:10AM

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

Avalanche Canada bcorrigan, Avalanche Canada

Use caution in areas that have not seen recent riding activity. The new snow will take time to stabilize.

Summary

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

A low pressure system moving into the area from the South West will pass through Saturday afternoon and Sunday morning bringing 10 to 20cm of moist snow to the region. Freezing levels will fluctuate between 500m overnight to 1000m in the afternoon on Sunday. Monday the freezing level will again rise to 1000 m with cloudy skies and the possibility of flurries.

Avalanche Summary

Reports from yesterday include several large ( 2-3) natural avalanches as well as a size 1, loose-wet avalanche below tree line.  Operators are also reporting impressive results with explosives, up to size 2.5.  Precipitation tonight and tomorrow will likely produce a new round of wind slab activity. In places where buried persistent weak layers exist, the likelihood of triggering wind-deposited snow will also increase the chance of affecting the storm slab. 

Snowpack Summary

Recent storms with strong southwest winds have redistributed the snow at tree line and above. Wind slabs have formed lee on slopes. Operators have reported moist-wet snow below 1800 metres. East of Crowsnest Pass, new snow overlies scoured surfaces or hard stubborn wind slabs from last week. In general, the mid and lower snowpack are strong and well-settled in these areas.In areas to the west of the divide there's a mix of weak crystals around 30 to 50cm below the surface. These crystals, that formed at the beginning of January, seem most reactive in open areas below treeline and consist of surface hoar, facets and a hard crust that formed on steep solar aspects. Additional snow load will add to the size and reactivity of this developing persistent slab. About 60cm below the surface you may also find a surface hoar layer which formed in December. Although no avalanches have been reported on this layer, it continues to produce sudden planar results in snowpack tests and could come into play with a large trigger such as a cornice, or simply additional storm loading.All areas have received extensive wind activity.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs at treeline and above are a very real concern at this time. Consider digging a pit to verify stability before venturing into new terrain.
Be aware of the potential for wide propagations due to the presence of hard windslabs.>Stay off recent wind loaded areas until the slope has had a chance to stabilize.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
This persistent weak layer could be triggered by a wind or storm slab and result in a large, destructive avalanche
Use extra caution on open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Jan 24th, 2016 2:00PM

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