Avalanche Forecast

Issued: Feb 1st, 2016 8:45AM

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

jlammers, Avalanche Canada

South Columbia.

Recently formed wind slabs have been slow to settle and gain strength.

Summary

Confidence

High

Weather Forecast

On Tuesday and Wednesday morning expect a mix of sun and cloud and light northwest winds. By Wednesday evening a Pacific system will make its way inland bringing 5-10cm of new snow and strong southwest winds. Freezing levels will stay at valley bottom for the forecast period.

Avalanche Summary

On Monday, a skier triggered a size 2 wind slab avalanche at about 2250m in the Revelstoke backcountry. The individual was taken for a ride, but was uninjured. I expect recently formed wind slabs will remain sensitive to human triggering on Tuesday. There is also the ongoing possibility of triggering more destructive persistent slab avalanches in isolated terrain.

Snowpack Summary

Recent storm loading brings storm slab thickness to 20-40cm and up to 50cm in wind loaded areas. The recently destructive persistent weak layer from early January is now typically down 70-110cm in most places and has recently produced some large, destructive avalanches in the region. The layer is slowly getting harder to human trigger but is still quite reactive in snowpack tests and has the potential for wide propagations. In general, the lower snowpack below this layer is well settled and strong.

Problems

Wind Slabs

A avalanche involvement in the Northern Selkirks shows that recently formed wind slabs should remain on our radar. Watch for increased sensitivity in the lee of ridge crests.

Avoid freshly wind loaded features. >Use ridges or ribs to avoid pockets of wind loaded snow. >Be cautious as you transition into wind affected terrain. >

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

Destructive persistent weaknesses buried up to 120cm below the surface have become less likely to trigger, but still deserve respect. I'd be increasingly cautious on steep, unsupported slopes around treeline.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar. >Be cautious around steep open slopes and convex rolls at and below treeline where buried surface hoar may be preserved. >

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 5

Valid until: Feb 2nd, 2016 2:00PM