Avalanche Forecast

Issued: Apr 12th, 2021 4:00PM

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

Avalanche Canada shorton, Avalanche Canada

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Danger will elevate throughout the day as slopes warm up. Plan your day around avoiding cornices and sun-exposed slopes. Read more in this Forecasters' Blog.

Summary

Confidence

Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

MONDAY NIGHT: Partly cloudy skies, 20 km/h southwest wind, freezing level steady around 1300 m with treeline temperatures around 0 C.

TUESDAY: Mix of sun and cloud, 20 km/h southwest wind, freezing level climbs from 1300 to 1700 m throughout the day, treeline temperatures climb to +4 C.

WEDNESDAY: Sunny, light southwest wind, freezing level climbs from 2000 to 2700 m throughout the day, treeline temperatures climb to +8 C.

THURSDAY: Sunny, light southwest wind, freezing level steady around 2800 m, treeline temperatures around +8 C.

Avalanche Summary

Warm sunny weather this week will likely cause wet loose avalanches on sun-exposed slopes and large cornice falls.

Over the weekend there were a few reports of size 2 human triggered slab avalanches around Shames and Kitimat. There were also numerous reports of large cornice failures (size 2-2.5), some of which triggered wind slab avalanches on the slopes below. Additionally, small (size 1) wet loose avalanches on solar aspects were reported at all elevations.

Snowpack Summary

Sunny skies and rising freezing levels will result in melting surfaces on solar aspects and lower elevations. 20-30 cm of recent snow is quickly settling and strengthening, although wind slabs could linger at upper elevations. The mid/lower snowpack is well settled and strong in most areas. Cornices are large and looming along ridgelines, and are capable of triggering avalanches when they fail.

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

  • Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet
  • Avoid exposure to slopes that have cornices overhead.
  • Loose avalanches may start small but they can grow and push you into dangerous terrain.
  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.

Problems

Loose Wet

An icon showing Loose Wet

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

Aspects: East, South East, South, South West, West.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Cornices

An icon showing Cornices

Strong solar radiation and warming will likely trigger the large cornices that hang over ridgelines.

Aspects: North, North East, East, West, North West.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1.5 - 2.5

Wind Slabs

An icon showing Wind Slabs

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

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Apr 13th, 2021 4:00PM