Avalanche Forecast

Issued: Feb 2nd, 2016 8:51AM

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. Use extra caution around ridge crests.

Summary

Confidence

High

Weather Forecast

On Wednesday evening, the first of 2 organized fronts will move through the region bringing 5-10cm of new snow and strong southwest winds. Thursday will see mainly overcast skies and continued strong ridgetop winds. By Friday evening, the second front will pass through the region. Expect another 5-10cm of snow and strong southwest winds. Freezing levels should remain at valley bottom for Wednesday and Thursday, and then rise to about 1500m for Friday.

Avalanche Summary

On Monday, a skier triggered a size 2 wind slab avalanche on a southwest aspect at about 2250m in the Revelstoke backcountry. The individual was taken for a ride, but was uninjured. Although existing wind slabs should gain strength over time, new snow and wind on Wednesday night should spark a new round of wind slab activity on Thursday . There is also the ongoing possibility of triggering more destructive persistent slab avalanches in isolated terrain.

Snowpack Summary

Snowfall and strong winds prior to last weekend created wind slabs that remain sensitive to light inputs in higher elevation lee terrain. The recently destructive surface hoar layer from early January is now typically down 80-120cm in most places. Although the layer has becomeÂ harder to human trigger and is variably reactive in snowpack tests, it still has the potential for wide propagations. With that, I would continue to show respect for this layer in steep, open terrain at treeline and below. In general, the lower snowpack below this layer is well settled and strong.

Problems

Wind Slabs

A recent avalanche involvement in the Selkirks shows that recently formed wind slabs should remain on our radar. Watch for triggering behind ridge crests and in gullies.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

Persistent slabs have become more difficult to trigger; however, avalanches failing on buried surface hoar would be large and destructive. Use increased caution in steep, open terrain at treeline and below.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 5

Valid until: Feb 3rd, 2016 2:00PM