Avalanche Forecast

Issued: Feb 5th, 2016 3:00PM

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

esharp, Avalanche Canada

Cariboos.

Watch for reactive storm slabs to form as the new snow settles. Tricky conditions still exist due to a touchy weak layer. Conservative terrain selection is critical.

Summary

Confidence

Moderate - Freezing levels are uncertain on Monday

Weather Forecast

SATURDAY: Up to 15cm snow overnight, with another 5cm possible thought he day, rain is expected at lower elevations, moderate to strong westerly winds, freezing level of 1500m overnight falling to 1000m in the day. SUNDAY: Mainly cloudy, light westerly winds, freezing level falling to valley floor though the day. MONDAY: sunny with cloudy periods, light westerly winds, freezing level around 2500-3000m, +5C at 2500m.

Avalanche Summary

The recent storm snow is becoming increasingly reactive with numerous small natural and human triggered avalanches reported in the last two days. The January surface hoar remains a concern. A size 3 natural avalanche that occurred earlier in the week at treeline near Blue River was reported to be around 1500m wide, demonstrating the ability of this layer to propagate and produce large destructive avalanches. On Sunday, a helicopter is believed to have remotely triggered a size 2.5 persistent slab avalanche at the 1900m elevation from a distance of 200m. This slab was about 400m wide, 90cm deep and is thought to have failed on the early January surface hoar. Although both of these avalanches occurred on the east side of Highway 5 (technically in the Northern Monashees), similar touchy conditions likely exist in many parts of the Cariboos.

Snowpack Summary

Up to 45cm of recent storm snow is settling to form a widespread soft slab. Moderate southwesterly winds have formed fresh wind slabs in lee features at treeline and in the alpine. Below 1800m this new snow is sitting on a crust. Several touchy layers of surface hoar from early to mid-January are now buried between 70 and 120cm deep and are variably reactive. In other words, some slopes are difficult to trigger while remote triggering is still possible on other features. These layers have the potential for wide propagations, and smaller avalanches could step-down to one of these layers. Snowpack depths are variable across the region and shallow snowpack areas may have weak facetted crystals near the ground.

Problems

Storm Slabs

Winds, new snow and warm temperatures are expected to create touchy conditions as the new snow settles to form a slab. Where rain falls on previously cold snow increased avalanche activity is expected.

Avoid steep, open slopes.>Avoid freshly wind loaded features.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

A cornice failure or a small avalanche in motion has the potential to step-down to a deeper weak layer. If triggered, this layer can still produce large, destructive avalanches.

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 6th, 2016 2:00PM