Northwest Coastal Avalanche Forecast

Issued: Apr 11th, 2021 4:00PM

Mon Apr 12th Current Conditions
Alpine Moderate Treeline Low Below Treeline Low
Tue Apr 13th 2 Day Outlook
Alpine Considerable Treeline Considerable Below Treeline Considerable
Wed Apr 14th 3 Day Outlook
Alpine Considerable Treeline Considerable Below Treeline Considerable

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Wind Slabs, Cornices and Loose Wet.

Lingering wind slabs may remain reactive to human triggers on lee features below ridgetops in the alpine. Use caution when transitioning into wind affected terrain and avoid slopes with large cornices overhead.

Summary

Confidence

High -

Weather Forecast

  

SUNDAY NIGHT: Clearing skies / Light, north ridgetop wind / alpine low temperature -11 / Freezing level valley bottom.

MONDAY: Sunny / Light, southwest ridgetop wind / alpine high temperature 2 / Freezing level 1400 m.

TUESDAY: Mix of sun and cloud / Light, southwest ridgetop wind / alpine high temperature 6 / Freezing level rapidly rising to 2500 m.

WEDNESDAY: Sunny / Light, southwest ridgetop wind / alpine high temperature 9 / Freezing level rising to 2900 m.

Avalanche Summary

Naturally triggered wind slabs on northeasterly aspects in the alpine up to size 2 were reported on Saturday. Additionally, small (size 1) wet loose avalanches on solar aspects were reported at all elevations.

Snowpack Summary

20-30 cm. of recent snow was accompanied by periods of strong winds from shifting directions which formed wind slabs on a variety of aspects at treeline and above. Recent snowfall amounts will vary widely throughout the region due to the convective nature of the spring weather.

The recent snow has covered a variety of snow surfaces, including wind affected snow, crusts on solar aspects and at lower elevations, and soft snow on sheltered slopes at upper elevations.

Cornices are large, looming, and capable of triggering large avalanches when they fail. 

The mid/lower snowpack is well settled and strong in most areas.

Glide cracks releasing as full depth glide slab avalanches become more common in the spring and are extremely difficult to predict. Best practice is to avoid slopes with glide cracks.

Terrain and Travel

  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Avoid lee and cross-loaded terrain.
  • Avoid exposure to slopes that have cornices overhead.
  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Possible

Expected Size

1 - 2

Lingering wind slabs formed by 20-30 cm. of recent snow and previously strong winds from shifting directions may remain reactive on lee features in the alpine.

Aspects:

All aspects.

Elevations:

Alpine.

Cornices

An icon showing Cornices

Likelihood

Possible

Expected Size

1.5 - 2.5

Cornices are large and looming along many ridgelines and have likely grown with the recent wind. 

Strong solar radiation and warming are common triggers for cornice failures which could trigger large avalanches.

Aspects:

North, North East, East, West, North West.

Elevations:

Alpine.

Loose Wet

An icon showing Loose Wet

Likelihood

Possible-Likely

Expected Size

1 - 1.5

Wet loose avalanches may start to run naturally on steep solar aspects when the sun comes out.

Aspects:

East, South East, South, South West, West.

Elevations:

All elevations.

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

Forecast Trend

The latest forecast danger ratings, broken down to elevation. See how an elevation is trending.