Avalanche Forecast

Slab avalanches to size 2 were reported on north and east facing slopes at higher elevations during Tuesday's storm.

On Wednesday a size 2.5 naturally triggered persistent slab was reported on a northwest facing slope in the alpine, where the bed surface had reloaded from a previous recent avalanche. Last Saturday, a very large avalanche was reported on Joffre shoulder. We suspect it failed on the weak layer of facets or surface hoar overlying a crust.

Up to 60 cm of light storm snow is being transported into wind slabs on south facing slopes from northerly winds. These slabs overly wind-affected surfaces and a layer of surface hoar in sheltered areas at treeline and below.

A crust is found at treeline and below, 40-80 cm down. In some areas, a layer of preserved surface hoar is found just above the crust.

Another weak layer of facets or surface hoar overlying a crust is found at the base of the snowpack down 80 to 120 cm. This is the suspected failure plane for a few large avalanches in the region that occurred on January 6.

Snowpack depths are 100 to 140 cm at treeline and decrease rapidly below.

Thursday Night

Mostly clear skies with 20-30 km/h northerly winds. Treeline temperature drops to -30 °C.

Friday

Sunny. Northerly winds 15-30 km/h. Treeline temperature remains steady around -30 °C.

Saturday

Sunny with northerly winds 10-20 km/h. Treeline temperatures rise to -20 °C.

Sunday

Sunny with northerly winds 20-40 km/h. Treeline temperatures rise to -20 °C.

With unusually cold temperatures forecast for this weekend, check out the most recent Forecaster Blog for tips on backcountry preparedness.

More details can be found in the Mountain Weather Forecast.

• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• Expect slab conditions to change drastically as you move into wind exposed terrain.
• Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.