Avalanche Forecast

Issued: Jan 19th, 2016 9:15AM

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

Avalanche Canada jlammers, Avalanche Canada

Lots of snowpack variability exists between the west and east sides of the region. Click the Forecast Details tab for more info.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

On Tuesday night up to 15cm of new snow is expected with generally light to moderate ridgetop winds. By the afternoon, we should expect a mix of sun and cloud and light northwest winds. On Thursday and Friday a series of Pacific systems will move through the region bringing up to 5cm of new snow and strong southwest winds each day. Freezing levels should sit at valley bottom on Wednesday and then rise to about 1800m on Thursday and Friday.

Avalanche Summary

In the Elk Valley North area on Tuesday, several natural wind slab avalanches to size 1.5 were observed in wind-loaded, high elevation terrain. A size 1 persistent slab avalanche was also noted on a steep cut bank below treeline. New wind and snow on Tuesday night may promote a new round of wind slab activity. In areas where buried persistent weak layers exist, new snow will also add to the likelihood and consequences of triggering the overlying slab.

Snowpack Summary

Up to 15cm of new snow may fall on Tuesday night. If ridgetop winds are moderate or greater, I would expect fresh and reactive wind slabs to form in high elevation lee terrain. East of Crowsnest Pass any new snow will overlie mainly 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 you're more likely to find a mix of persistent weak crystals which may lie up to 30cm below the surface. These crystals, which formed at the beginning of January, seem most reactive in open areas below treeline and consist of surface hoar, facets and a hard crust on steep solar aspects. Additional snow load will add to the size and reactivity of this developing persistent slab.

Problems

Wind Slabs

An icon showing Wind Slabs
Up to 15cm of new snow may fall on Tuesday night. If ridgetop wind speeds are moderate or greater, fresh and reactive wind slabs will form at higher elevations.
Be alert to conditions that change with elevation.>Stay off recent wind loaded areas until the slope has had a chance to stabilize.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
Up to 30cm of cohesive storm snow overlies a mix of weak crystals which seem most reactive at below treeline elevations west of the divide. Watch for triggering in steep open glades and in cut blocks.
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 20th, 2016 2:00PM