North Columbia

Snowfall should ease on Wednesday, but strong alpine winds will continue. Dangerous avalanche conditions are likely to persist at higher elevations.

Moderate

• We are uncertain about forecast snowfall amounts.
• We are confident that there are persistent slabs in the snowpack, but uncertain about how likely they are to trigger.

After last week’s avalanche cycle, cooler temperatures have rapidly reduced activity.

Since the weekend, several small (size 1) slab avalanches have been both human and naturally triggered in wind-loaded alpine terrain. A few large (up to size 3) slabs have also been triggered by cornice failures, both natural and explosive-controlled.

With the recent arrival of new snow and strong winds, avalanche likelihood and potential size will increase.

As much as 50 cm of new snow has accumulated at higher elevations, with amounts decreasing rapidly at lower elevations. Strong alpine winds have redistributed this snow in exposed terrain, creating areas of deeper wind loading.

Below approximately 2200 m, a thick crust with widespread rain runnels exists beneath the new snow. Moist snow is present below this crust.

Above 2200 m, a thinner crust or moist snow may be found beneath the recent storm snow.

Deeper weak layers may persist within the snowpack, particularly at higher elevations. However, due to the overall strength and depth of the upper snowpack, these layers are considered unlikely to be triggered.

Tuesday Night
Mostly cloudy. 2 to 4 cm of snow. 60 km/h southwest ridgetop wind. Treeline temperature -3 °C.

Wednesday
Mostly cloudy. 2 to 10 cm of snow. 40 km/h southwest ridgetop wind. Treeline temperature -6 °C.

Thursday
Mostly cloudy. 5 to 10 cm of snow. 30 km/h west ridgetop wind. Treeline temperature -9 °C.

Friday
Mix of sun and clouds. 40 km/h southwest ridgetop wind. Treeline temperature -7 °C.

More details can be found in the Mountain Weather Forecast.

• Avoid freshly wind-loaded features, especially near ridge crests, rollovers, and in steep terrain.
• Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
• Be alert to conditions that change with aspect and elevation.