Avalanche Forecast

Issued: Mar 4th, 2021 4:00PM

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

Avalanche Canada astclair, Avalanche Canada

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With heavy precipitation and strong winds on Friday, natural avalanches are likely. Consider your ability to recognize and avoid terrain as travel in avalanche terrain is not recommended. 

Summary

Confidence

High - We are confident the likelihood of avalanche will increase with the arrival of the forecast weather.

Weather Forecast

A powerful storm is impacting the region

Thursday night: Overcast, 25-35 cm of snow possible over 1300 m with rain below, strong south wind.

Friday: Overcast, another 25-35 mm of precipitation with snow line dropping from 1500 m to 1000 m throughout the day, strong southwest wind with extreme gusts.

Saturday: Mostly cloudy, 10-20 cm of snow, moderate south winds, freezing level near 800 m. 

Sunday: Mostly cloudy, 10-20 cm of snow, strong southwest winds, freezing level near 800 m. 

Avalanche Summary

Natural and human-triggered avalanches are likely on Friday.

This MIN from Sky Pilot on Sunday describes cornice debris around 1600 m. 

There have been no reports of avalanche activity over the February 24th crust layer since last Thursday, when small to large (size 1-2) skier triggered avalanches were reported on all aspects.

Snowpack Summary

Areas at upper elevations could see as much as 40-60 cm of snow accumulate by the end day on Friday. Strong south winds will contribute to rapid slab formation, making natural avalanches likely. The combination of wind and snow has the potential to weaken cornices, which can act as triggers on slopes below.

Deeper in the snowpack, a widespread hard rain crust is buried that formed at the end of February. This crust can be found all the way to the tops of the North Shore mountains. Reports indicate that the snow above is bonding well to the crust. 

The snowpack below the rain crust is well settled and strong in most areas. 

Terrain and Travel

  • Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.
  • Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
  • Watch for changing conditions today, storm slabs may become increasingly reactive.

Problems

Storm Slabs

An icon showing Storm Slabs

Heavy snowfall on Friday is expected to rapidly accumulate above 1300 m, forming a widespread reactive storm slab problem. Storm slabs may be more reactive in wind-drifted areas. The combination of wind and snow has the potential to weaken cornices, which can act as triggers on slopes below.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1.5 - 2.5

Loose Wet

An icon showing Loose Wet

Heavy rain at lower elevations may initiate loose wet avalanches. A saturated snow surface, pinwheeling, or point releases from rocks are good indicators of this instability.  

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Likely

Expected Size

1 - 1.5

Valid until: Mar 5th, 2021 4:00PM