Storm snow has added load to a complex upper snowpack creating dangerous avalanche conditions.
Step-down avalanches are possible, stick to lower angle terrain with no overhead hazard.
Weak layers in the upper snowpack consisting of surface hoar/crust/facets continue to be loaded by new snow. A recent report of a very large persistent slab avalanche is proof that weak layers deeper in the upper snowpack remain a concern.
Recent storm snow up to 30 cm has added load to a complex upper snowpack. Storm slab avalanches could step down to deeper weak layers described in the snowpack summary.
On Tuesday there were several reports of size 2 explosives triggered, skier controlled and natural storm slab avalanches running on surface hoar buried in mid-February.
On Monday, a size 3 skier remote (triggered from a distance) avalanche was reported in the Qua area near Nelson.
Several Mountain Information Network posts describe human-triggered and remotely triggered slab avalanches failing on crusts and/or surface hoar layers down roughly 30-50 cm.
20 to 25 cm of storm snow has buried a complex upper snowpack. This region is highly variable with similar weak layers that vary widely in depth and distribution:
On February 13th a surface hoar layer and/or a crust on solar aspects was buried.
On February 7th a surface hoar layer/crust layer (depending on aspect) was buried.
On January 26th, a surface hoar/crust layer sitting on a facet layer was buried and is down 60 to 80 cm.
This weak snowpack structure will continue to produce avalanches as storm snow settles.
The mid and lower snowpack remain well settled.
Wednesday Night
Partly cloudy. 2 to 4 cm of snow. 10 km/h southwest ridgetop wind. Treeline temperature -12 °C.
Thursday
Mostly cloudy. 2 to 5 cm of snow. 15-25 km/h southwest ridgetop wind. Treeline temperature -9 °C.
Friday
Mostly sunny. 10-20 km/h north ridgetop wind. Treeline temperature -8 °C.
Saturday
Mostly sunny. 20-30 km/h south ridgetop wind. Treeline temperature -6 °C.
More details can be found in the Mountain Weather Forecast.
