New snow and wind have formed reactive storm slabs at all elevations. Conservative terrain choices will be critical to playing safe on Friday.
Expect hazard to be HIGH in portions of the region that receive 20 cm. or more snow Thursday night.
A persistent weak layer 50-100 cm deep continues to show reactivity in snowpack tests, despite not producing avalanches in the past week. This surface hoar/crust interface may remain human triggerable in steep convex features at treeline and potentially steep alpine features where it presents as a crust.
20 cm. of new snow and strong westerly winds have formed storm slabs that are expected to remain reactive to human triggers; especially in wind affected terrain.
THURSDAY NIGHT: Snow; 10-20 cm. / Strong, west ridgetop wind / Alpine low -10 / Freezing level valley bottom.
FRIDAY: Cloudy with flurries; 3-5 cm. / Light, northwest ridgetop wind / Alpine high -4 / Freezing level 1200 m.
SATURDAY: Mix of sun and cloud / Light, northwest ridgetop wind / Alpine high -5 / Freezing level 1000 m.
SUNDAY: Mix of sun and cloud / Strong, northwest ridgetop wind / Alpine high -4 / Freezing level 1200 m.
No new avalanches were reported in this region on Wednesday. However, the incoming snow and strong west winds are expected to form storm slabs reactive to human triggers.
20 cm. of new snow and strong southwest winds on Thursday have formed fresh storm slabs that will be reactive to human triggers.
Weak surface hoar sitting on a crust on solar aspects was reported in the Kootenay Pass area prior to the storm. This layer may also be present in other areas within the region. Storm slabs will be more sensitive to human triggering in areas where this weak layer was preserved before being buried; especially if the surface hoar is sitting on a crust.
The main persistent layer of concern below the surface is a combination of surface hoar, facet, and crust layers that formed in January that are now buried 60-150 cm. deep. Steep, open slopes at treeline elevations are the most likely spots to trigger a large avalanche on this layer.
