South Columbia

New wind slabs are expected to form this weekend as a weak storm progresses. Continually assess local conditions as you travel and use extra caution as you transition into wind affected terrain.

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Mostly cloudy conditions are expected on Saturday as a storm system approaches the region. Light intermittent snowfall is possible during the day with alpine winds increasing to moderate to strong from the SW. Treeline temperatures are expected to be around -12C during the day. The main part of the storm is expected to affect the region Saturday night and Sunday. 4-8cm of snowfall is possible for the snowy parts of the region. Alpine winds are expected to remain moderate to strong from the SW and treeline temperatures will climb to around -8C. Unsettled conditions are expected on Monday as the remnants of the storm are pushed out by a ridge of high pressure.

On Wednesday, two natural size 2.5 glide crack releases were reported but no details were attached. Four small natural wind slabs were also reported from steep NW aspects in the alpine.  Minor natural sluffing from steep terrain was also reported in the region on Wednesday. No natural avalanches were reported on Thursday and explosives only triggered loose sluffing from steep slopes on a variety of aspects. 

At higher elevations, 30-50cm of low-density snow typically overlies old stubborn wind slabs which formed last weekend. The reports we have received suggest a good bond within the storm layers in the upper snowpack. New wind slabs are expected to form this weekend as winds increase with the approaching storm.  Between 80 and 130cm below the surface you'll likely find a weak layer surface hoar which was buried in early December. This layer is most widespread at lower elevations (between 1400m and 1800m.) Field reports indicate triggering this layer has become unlikely. That said, if it does fail the overlying slab is stiff enough to propagate over a wide distance. Below this layer, the snowpack is thought to be generally strong and well-settled.