Avalanche Forecast

Moderate - Uncertainty is due to the limited number of field observations.

  

TUESDAY NIGHT: Partly cloudy / Light, northwest ridgetop wind / Alpine low -14 / Freezing level valley bottom.

WEDNESDAY: Sunny / Light, northwest ridgetop wind / Alpine high -3 / Freezing level 1200 m.

THURSDAY: Snow; 5-10 cm. / Strong, southwest ridgetop wind / Alpine high -3 / Freezing level 1200 m.

FRIDAY: Cloudy with isolated flurries; 0-3 cm. / Light, northwest ridgetop wind / Alpine high -3 / Freezing level 1100 m.

On Tuesday, explosive control work on Kootenay Pass produced numerous wind slabs up to size 2.5 on primarily south aspects, with crowns up to 100 cm. in wind loaded features.

There were many reports of human triggered persistent slab avalanches during the first two weeks of February. These avalanches failed on a surface hoar layer that is now 50-100 cm deep and is most prevalent at treeline elevations. There were also two very large explosive triggered avalanches in the Bonningtons in the past month that stepped down to the early December crust (most recently on Feb 9). These deeper instabilities have been trending towards being unreactive, however occasional snowpack tests suggest they may still be possible to trigger in isolated areas.

25-50 cm of recent snow and strong southwest winds have formed reactive wind slabs on lee and cross loaded features at treeline and above.

The main persistent layer of concern is a combination of surface hoar, facet, and crust layers that formed in January that are now buried 50-100 cm deep. No avalanches have been reported on this layer in the past week. Steep, open slopes at treeline elevations are the most likely spots to trigger a large avalanche on this layer.

• Be careful as you transition into wind affected terrain.
• Avoid lee and cross-loaded terrain.
• Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
• Be aware of the potential for large avalanches due to the presence of a persistent slab.