North Columbia

Warm temps and strong sun are likely to cause cornices to fail, potentially triggering the persistent slab.

Wet loose avalanches are very likely with a warm night and incoming sun.

On Friday, numerous large (size 2) explosive triggered cornice avalanches where reported. Additional reports of large naturally occurring loose wet avalanches where observed in the afternoon.

On Thursday, a few large (size 2) wet loose avalanches where observed.

Large natural cornice failures continue to be reported and are a prime suspect for triggering large persistent slab avalanches.

On the surface, up to 30 cm of recent snow exists on northerly aspects in the alpine. Solar aspects and lower elevations will present a crust or moist snow.

Below this, a 5 to 25 cm variable strength crust from last week's rain event is present. This is capping a moist upper snowpack.

The primary weak layer of concern was buried in early March consisting of surface hoar, facets, and a crust is now 80 to 150 cm deep.

Deeper weak layers from February and January are buried 150 to 200 cm deep.

Saturday Night

Clear. 10 to 15 km/h southwest ridgetop wind. Treeline +3 °C. Freezing level 2500 m.

Sunday

Sunny with increasing clouds in the afternoon. 20 to 50 km/h southwest ridgetop wind. Treeline temperature +6 °C. Freezing level rising to 3000 m.

Monday

Cloudy with snow and rain 5 to 10 cm . 15 to 20 km/h southwest ridgetop wind. Treeline temperature 0 °C. Freezing level 2000 m.

Tuesday

Cloudy with snow and rain 5 to 10 cm. 20 to 50 km/h southwest ridgetop wind. Treeline temperature -2 °C. Freezing level 1200 m.

More details can be found in the Mountain Weather Forecast.

• Cornice failures could trigger large and destructive avalanches.
• Travel early on sun-exposed slopes before cornices weaken with daytime warming.
• The more the snowpack warms up and weakens, the more conservative your terrain selection should be.