Avalanche Forecast

Issued: Jan 11th, 2021 4:00PM

The alpine rating is high, the treeline rating is high, and the below treeline rating is considerable. Known problems include Storm Slabs and Loose Wet.

Avalanche Canada swerner, Avalanche Canada

Natural avalanches are expected on Tuesday with reactive storm slabs at higher elevations above the rain/snow line and loose wet avalanches below. Travel in avalanche terrain is not recommended. 

Summary

Confidence

Moderate - Forecast precipitation (either snow or rain) amounts are uncertain. We are confident the likelihood of avalanche will increase with the arrival of the forecast weather.

Weather Forecast

Yet another strong Pacific frontal system is slated to hit the Coastal regions tonight and persist until Wednesday morning bringing rising freezing levels, heavy precipitation, and strong to extreme wind. 

Monday Night: 20 – 30 mm of rain/snow with freezing levels near 1400 m. Ridgetop wind strong from the southeast.

Tuesday: 25-45 mm of rain/ snow (only on the highest peaks) with forecast freezing levels 2000 m. Ridgetop wind strong-extreme from the South. 

Wednesday: Generally a drying and cooling trend bringing a mix of sun and cloud, light southwesterly wind, and freezing levels near 900 m. 

Avalanche Summary

Natural avalanche activity will likely be the theme on Tuesday during and after the storm, with loose wet activity below the snow-rain line and storm and wind slab activity above.

Snowpack Summary

60-80 mm of precipitation is forecast to accumulate Monday night through to early Wednesday morning, with it falling as snow above around 1700 m and rain below. This means that only the highest peaks will receive snow. 

Above the snow-rain line, storm and wind slabs are expected to rapidly form and be reactive. Below the snow-rain line, wet loose avalanches will likely occur on all aspects. This is a significant amount of precipitation that will dramatically weaken the snowpack creating avalanches on Tuesday. This is a good time to wait out the storm and let the snowpack adapt, adjust, and strengthen before heading out into the backcountry.

The remainder of the snowpack is well-consolidated.

Terrain and Travel

  • Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.
  • Travel in alpine terrain is not recommended.
  • Watch for unstable snow on specific terrain features, especially when the snow is moist or wet.
  • The more the snow feels like a slurpy, the more likely loose wet avalanches will become.

Problems

Storm Slabs

An icon showing Storm Slabs

Snow accumulation (forecast above 1700 m) above the snow-rain line will likely build reactive slab avalanches. Slabs will be thickest in lee terrain features, as the snow will fall with strong southwest wind. Avoid avalanche terrain if you find more than 30 cm of snow accumulation.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely - Almost Certain

Expected Size

1 - 2.5

Loose Wet

An icon showing Loose Wet

Rain will soak the snowpack below the snow-rain line. Natural and human triggered wet snow avalanches are likely on Tuesday. 

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Very Likely - Almost Certain

Expected Size

1 - 2

Valid until: Jan 12th, 2021 4:00PM