A sudden change in weather can have surprising effects on the snowpack. Conservative terrain use is key.
Confidence
Moderate - Freezing levels are uncertain on Tuesday
Weather Forecast
TUESDAY: Flurries with 3-5 cm of new snow, strong southwest winds, freezing level rapidly rising to around 1500 m.WEDNESDAY: Flurries with 5-15 cm of new snow, strong southwest winds, freezing levels around 1600 m.THURSDAY: Cloudy with isolated flurries, strong southwest winds, freezing levels around 1400 m.
Avalanche Summary
Several natural and human triggered size 1 wind slabs were reported on Monday. Over the weekend, widespread loose dry avalanches were reported, suggesting there's still lots of soft snow available to transport. Expect fresh wind slabs to form when the winds pick up on Tuesday.
Snowpack Summary
Increasing winds are causing widespread wind affect in exposed alpine and treeline terrain and forming touchy wind slabs on lee features. Last week, 20 cm of low density snow buried a plethora of old surfaces (wind scoured, old wind slabs, surface hoar up to 20 mm in sheltered terrain, and/or faceted old snow). Deeper in the snowpack, the mid-December persistent weak layer of facets has been more prominent and reactive in the Corbin area than areas closer to Fernie. The layer is generally considered dormant at the moment in deeper snowpack areas, but its status may change as the temperatures warm throughout the week.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.