Highly sensitive storm slabs overlying surface hoar are reactive in all elevation bands. Conservative terrain selection is essential for safe travel.If the sun is out in full strength on Wednesday, use extra caution on steep south facing slopes.
Summary
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain on Thursday
Weather Forecast
A weak ridge of high pressure should result in mainly dry and sunny conditions for Wednesday. Freezing levels are expected to be around 1200m and alpine winds should be light from the southwest. A fairly substantial storm system is expected to arrive Wednesday overnight or Tuesday morning. Models are currently showing snowfall accumulations of 50cm or more for the region by Thursday night. Alpine winds are expected to be strong from the southwest during the storm. Freezing levels during the storm are uncertain with one model showing around 1500m and another showing as high as 2300m on Thursday afternoon. The storm will likely continue on Friday morning but is expected to clear out by the end of Friday.
Avalanche Summary
On Monday, explosives triggered numerous slab avalanches size 1.5-2. Ski-cutting produced a couple size 1 storm slabs on east aspects at 1800m. A skier also remotely triggered a size 1.5 avalanche from 10m away on a NW aspect at 1750m. The majority of the avalanches reported were failing on the early January surface hoar layer down 40-80cm. There are a few more public reported avalanches on the Avalanche Canada Mountain Information Network as well as the South Coast Backcountry Touring facebook page with some great photos that are definitely worth checking out. Reports from Sunday include numerous Size 1-2 storm slab avalanches direct and remotely triggered by skiers on slopes as low-angled as 20 degrees, as well as widespread whumpfing in flatter terrain as low as 1300m.
Snowpack Summary
Approximately 60-100cm of storm snow has accumulated in the last two weeks and is bonding poorly to a widespread layer of surface hoar, facets, and/or sun crust from early January. Recent snowpack tests produced clean and sudden fractures on both these weaknesses with only moderate force. The mid and lower snowpack is generally strong, with the exception of shallower snowpack areas that may be more faceted. At lower treeline elevations recent rains have saturated the upper snowpack. At higher elevations moderate to strong southwest winds have recently loaded lee features at treeline and in the alpine.
rbuhler,
Avalanche Canada
