South Coast Inland Avalanche Forecast

Issued: Apr 10th, 2021 4:00PM

Sun Apr 11th Current Conditions
Alpine Moderate Treeline Moderate Below Treeline Low
Mon Apr 12th 2 Day Outlook
Alpine Moderate Treeline Moderate Below Treeline Low
Tue Apr 13th 3 Day Outlook
Alpine Moderate Treeline Low Below Treeline Low

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

Stay tuned in to hazards lingering from the storm. Wind slabs perched in steep leeward pockets, looming cornices, and fresh snow seeing its first sun exposure will all need to be managed on Sunday. Greater new snow accumulations mean greater hazard in the south of the region.

Summary

Confidence

High -

Weather Forecast

Saturday night: Clearing. Light northwest winds.

Sunday: Mainly sunny. Light north winds. Alpine high temperatures around -6 with freezing levels to 1400 metres.

Monday: Mainly sunny. Light northeast winds. Aline high temperatures around -3 with freezing levels to 1700 metres.

Tuesday: Sunny. Light to moderate northeast winds. Alpine high temperatures around 0 with freezing levels to 2000 metres.

Avalanche Summary

We don't yet have reports showing the results of Friday's storm, but it's likely that surface instabilities were quite active on Saturday, with a mix of wind slab hazards in higher elevation, wind exposed terrain, potentially storm slabs over slippery crust lower down, and natural loose wet activity where sun poked out to destabilize surface snow. This mix of hazards was almost certainly more pronounced in the south of the region, which saw 2-3 times the accumulations of the north.

Looking forward, the new snow is likely to form a reasonable bond with the old surface by Sunday, however recently wind loaded areas and slopes that see solar warming should remain suspect over the near term.

Snowpack Summary

About 10 cm of new snow fell in the north of the region through Friday night, closer to 20-30 cm near the Coquihalla, with amounts tapering off with elevation. Moderate to strong southwest winds accompanied this snowfall, moving snow into thicker, more reactive slabs in leeward terrain features. The new snow adds to 10-20 cm that fell last weekend. 

Collectively, this new and recent snow sits on a crust in most areas, except on north aspects above about 1500 m where it sits on older wind slabs or soft snow, depending on wind exposure.

Cornices are large and looming along ridgelines and they formed fragile new growth during the storm. Their release is unpredictable, requiring a large berth if you're travelling above or below them.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Loose avalanches may start small but they can grow and push you into dangerous terrain.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Possible

Expected Size

1 - 2

Slab problems are likely to be restricted to wind loaded features by Sunday, but pinning down slab distribution may be tricky with winds that shifted north after the storm. Analyze slopes for wind loading patterns and test small, low-consequence features before stepping out. This problem will be most pronounced in the south of the region.

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Loose Wet

An icon showing Loose Wet

Likelihood

Likely

Expected Size

1 - 1.5

Surface snow will lose cohesion and become unstable with solar warming during the day. Avoid exposing yourself to terrain where a small wet loose release could have big consequences.

Aspects:

South East, South, South West, West.

Elevations:

All elevations.

Cornices

An icon showing Cornices

Likelihood

Possible-Likely

Expected Size

2 - 3

Cornices are large and looming along many ridgelines, and have likely formed fragile new growth with recent snow and wind.  

Aspects:

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

Elevations:

Alpine.

Valid until: Apr 11th, 2021 4:00PM

Forecast Trend

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