Purcells

Persistent slabs sitting on a weak layer of surface hoar remain likely to human trigger.

Strong west winds may form reactive wind slabs in open terrain.

Moderate

• We are uncertain about how quickly persistent slabs are gaining strength.

Numerous persistent slab avalanches up to size 3 were reported on all aspects and elevations over the past few days. Avalanches have been triggered accidentally, naturally, and remotely.

See recent MIN reports here and here for further details.

Up to 20 cm of recent snow accompanied by strong southwest wind has formed deeper deposits on north and east aspects. In sheltered terrain it will overlie a layer of surface hoar or a sun crust. The snow surface is expected to become moist on sun exposed slopes.

A couple concerning weak layers exist in the upper snowpack:

• 60 to 80 cm deep, there is a supportive crust on south-facing terrain. On north-facing terrain, this layer maybe a breakable crust or surface hoar.

• The late January layer is buried 70 to 120 cm deep. It consists of a crust with facets or surface hoar above it.

The mid and lower snowpack is well settled.

Tuesday Night
Partly cloudy. 50 km/h west ridgetop wind. Treeline temperature -8 °C.

Wednesday
Mostly cloudy. 60 km/h west ridgetop wind. Treeline temperature -8 °C.

Thursday
Cloudy. 2 to 5 cm of snow. 70 km/h west ridgetop wind. Treeline temperature -7 °C.

Friday
Mostly cloudy. 5 to 10 cm of snow. 60 km/h southwest ridgetop wind. Treeline temperature -5 °C.

More details can be found in the Mountain Weather Forecast.

• In times of uncertainty, conservative terrain choices are our best defense.
• Watch for signs of instability like whumpfing, hollow sounds, shooting cracks, or recent avalanches.
• Be aware of the potential for remote triggering and large avalanches due to buried surface hoar.
• Strong wind is building wind slabs farther downslope than usual.
• Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.