Avalanche Forecast

Moderate - Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack.

Tuesday night: Scattered flurries. Light to moderate northwest wind. Freezing level 500 m. Alpine temperature -9.

Wednesday: Sunny. Light to moderate gusty southwest wind. Freezing level 1900 m. Alpine temperature -2.

Thursday: Flurries up to 5 cm. Moderate southwest wind. Freezing level 1700 m. Alpine temperature -5.

Friday: Flurries up to 10 cm. Light to moderate southwest wind. Freezing level 1500 m. Alpine temperature -7.

A natural storm slab avalanche cycle was observed to have run during the storm, widespread size 3-3.5 in the Selkirks and to a more limited extent in the Monashees to size 2, a few of them cornice-triggered. Storm slabs remained reactive to ski cuts on Monday, mostly around size 1 with a couple of skier remotes size 1-2 in the east of the region. By Tuesday, storm slabs were showing signs of becoming more stubborn, showing limited propagation with a few explosive control results around size 2. A skier triggered size 2.5 involvement in neighboring Glacier National Park resulted in lost gear and minor injuries.

Notable reports of avalanche activity prior to the storm include:

• A size 3 slab avalanche was observed northeast of Revelstoke on Wednesday. The avalanche failed on the ground on a south aspect at 1600 m. 
• In neighboring Glacier National Park and South Columbia regions, several natural cornice falls triggered deep slab avalanches size 2-3.

20-50 cm of recent snow in the Selkirk mountains and 5-10 cm elsewhere has seen some redistribution by southwest to northwest wind, and seems to be bonding well with underlying surfaces. Dry snow that sees direct sun or experiences above freezing temperatures for the first time Wednesday may become reactive as it settles rapidly. Crusty surfaces below treeline will become moist with rising freezing levels.

At alpine and treeline elevations, a widespread crust exists (except on north-facing slopes above 1800 m) buried 50-100 cm deep. Overall the snow seems to be bonding well at this interface, although there have been a few isolated avalanches running on crust layers over the past few week.

• Extra caution for areas experiencing rapidly warming temperatures for the first time.
• Remember that in the spring strong solar radiation and warm temperatures can weaken the snow in a matter of minutes.
• Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.
• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.