Avalanche Forecast

Saturday Night: Clear. No new snow expected. Light to moderate north ridgetop wind. Freezing level falls to valley bottom. Alpine low around -7 °C.

Sunday: Sunny. No new snow expected. Light northwest ridgetop wind, trending to moderate at higher elevations. Freezing level rising to 1500 m through the day. Alpine high around -5 °C.

Monday: Partly cloudy. No new snow expected. Moderate northwest ridgetop wind, trending to extreme in at higher elevations. Freezing level at valley bottom overnight, rising to 1600 m through the day. 

Tuesday: Increasing cloud through the day. 2-5 cm of snow expected. Light, variable ridgetop wind. Freezing level stays at valley borrom, alpine temperature around -10 °C.

On Saturday, south of Nelson, small loose wet avalanches were reported on solar aspects. No other reports before 4 pm.

On Friday, south of Nelson, a large, remotely triggered slab avalanche was reported on a northeast aspect around treeline. The avalanche was triggered by a snowmobile, and it started on a steep, rocky, unsupported slope near a ridgetop. Also south of Nelson, natural loose wet avalanches were reported up to size 1.5 in the afternoon on steep solar aspects. East of Kelowna, a natural windslab avalanche and several explosive triggered windslabs were reported up to size 1.5 on east through south aspects around treeline. 

Additionally, east of Slocan (in the neighboring South Columbia region), a snowmobile rider triggered a size 2 slab avalanche on a northeast aspect around treeline. They were partially buried and injured. More details and photos here. The same group also remote triggered another avalanche on a solar aspect from 50 m away. 

On Thursday, south of Nelson, avalanche control with explosives triggered several small to large avalanches, failing below the crust that formed on Wednesday.

5-20 cm of new snow sits on a 1-5cm rain crust that goes as high as 2250 m in some parts of the region. There are a few great Mountain Information Network posts that describe the challenging backcountry travel conditions on Thursday due to this crust. 

Some places in the Kootenay Boundary have received over 60 mm of water over the course of the storm that started in the last few days of February. That has translated to about 20-50 cm (depending on elevation) of settled snow. This recent storm snow sits on a variety of hard surfaces, and feathery surface hoar crystals in some locations.

Weak layers from mid-February and late January made up of crusts and/or surface hoar crystals can be found around 60-100 cm deep. Some recent persistent slab avalanches on this layer have surprised riders, so keep this type of avalanche in mind when making terrain choices.

• Approach steep, open and/or sparsely treed slopes cautiously.
• Avoid steep convexities or areas with a thin, rocky, or variable snowpack.
• Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
• A crust on the surface will help bind the snow together, but may make for tough travel conditions.
• Closely monitor how the new snow is bonding to the crust.