South Columbia

Storm slabs are easy to trigger and long fracture propagations are possible. If the sun comes out, watch for natural avalanche activity on steep southerly aspects.

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

A weak ridge of high pressure is building over the interior ranges. Some light flurries can be expected overnight with moderate alpine winds from the northwest. Alpine temperatures should be around -10 on Friday with periods of broken sky or scattered cloud. There may be some solar warming on steep southerly aspects. The next storm is forecast to move inland from the coast on Saturday. There is some uncertainty regarding the timing and intensity of this next storm. Today it looked like the storm may arrive in the interior as early as Saturday morning, resulting in 5-10 cm combined with strong southwest winds during the day. If this timing holds true, expect another 5-10 cm on Sunday with strong southerly winds. These snowfall numbers may be low for upslope areas in the western Monashees.

Avalanche control in the highway corridor on Thursday resulted in numerous storm slab releases size 2.0-2.5 on various aspects between 900-1300 metres. Storm slab avalanches up to size 3.0 in the Rogers Pass on Wednesday. Several operations reported skier remote avalanches up to size 2.0 and skier controlled or accidental avalanches up to size 1.5 on Wednesday. The storm snow is settling into a cohesive slab that allows for long fracture propagations and remote triggering. I expect that the likelihood of triggering will be reduced on Friday with the forecast cooling, but will then increase again with Saturdays forecast Pacific storm.

Another 10-15 cm of new snow has combined with recent snow to make storm snow totals of 30-50 cm. The storm snow is settling into a cohesive slab that may allow for long fracture propagations. Wind transported snow at higher elevations may be easy to trigger, and could release storm slabs while they are in motion. Some areas have reported a thin freezing drizzle crust on the surface before the Wednesday morning snow arrived. There is about 50 cm above the surface hoar, facets, and sun crusts that were buried early in January. Buried surface hoar layers may be reacting to the increased load and developing slab properties below treeline in large openings like cut blocks.