Avalanche Forecast

Issued: Feb 17th, 2014 9:54AM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Storm Slabs.

ghelgeson, Avalanche Canada

Cariboos.

There's been a surprising lack of large natural avalanche activity, leading me to believe that many slopes remain at the brink of failure. I suspect this region is currently primed for human triggered avalanches.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Synopsis: Another pacific frontal system passes over the region late Tuesday accompanied by robust SW winds. Freezing levels should drop behind the system as isolated flurries linger in its wake.Tuesday: Freezing Level: 800m; Precip: 1/2mm - 1/4 cm; Wind: Mod/Strong SWTuesday Night: Precip: 5/6mm - 7/9 cm; Wind: Mod W | Strong W at ridgetop Wednesday: Freezing Level: 700m; Precip: 1/3mm 2/5 cm; Wind: Strong, WestThursday: Freezing Level: 600m; Precip: 1/3mm 2/5 cm; Wind: Mod, SW

Avalanche Summary

Recent observations are limited, but a widespread natural avalanche cycle occurred across the region over the last few days with natural and human triggered avalanches to size 2 at all aspects and elevations. There seams to be a propensity for remote triggering in this region. The overall lack of large avalanche activity is actually a little concerning.

Snowpack Summary

The never ending storm has produced 60 - 100 cm of total snowfall across the region which is settling into a cohesive slab that averages 45 - 80 cm in depth. This slab rests on a nasty persistent weak layer (Late Jan/Early Feb.) surface hoar/facet/crust combo that was formed during the month of cold clear weather. Professionals report numerous whumphs and significant propagation potential. Field observations continue to report easily triggered sudden planar failures on this interface in snowpack tests. Natural avalanches have been widespread and destructive. The keyword in Persistent Weak Layer is Persistent, I expect touchy conditions to remain in place longer than we're normally accustomed to due to the pervasive nature of this weakness. Ongoing strong winds out of the SW and W have loaded lee aspects and affected the snow at all elevations, but the affect is most prevalent at and above treeline. More strong winds in the forecast are expected only to add to this problem.Weak basal facets exist in some areas, but triggering has now become unlikely. For the most part, the mid and lower snowpack are strong and well consolidated.

Problems

Storm Slabs

The storm slab has mass and some serious bite. You can have a great day in the mountains with a very conservative approach. Watch for any increase in winds, fresh sensitive wind slabs can form in open terrain surprisingly quickly.

Avoid all avalanche terrain during periods of heavy loading from new snow or wind.>Use very conservative route selection, stick to moderate angled terrain with low consequence.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Be aware of the potential for remote triggering and large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 5

Valid until: Feb 18th, 2014 2:00PM