Avalanche Forecast

Issued: Mar 5th, 2022 4:00PM

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.

Avalanche Canada rbuhler, Avalanche Canada

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Ongoing wind slab formation is expected on Sunday in exposed terrain at higher elevations due to periods of moderate northerly wind. Use extra caution around cornices and steep south-facing slopes during the heat of the afternoon. 

Summary

Confidence

Low - Uncertainty is due to the limited number of field observations. Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack. Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack.

Weather Forecast

A ridge of high pressure brings one more day of dry and sunny conditions for Sunday before conditions change on Monday. 

Saturday Night: Clear, moderate N wind, freezing levels around 2000 m with an inversion.

Sunday: Mainly sunny, moderate to strong N wind, freezing levels reaching as high as 2500 m with an inversion.

Monday: Mainly cloudy with sunny breaks, strong NW wind, freezing levels 1500-1800 m.

Monday night and Tuesday: Periods of light snowfall, moderate to strong NW wind, freezing levels around 1000 m.

Avalanche Summary

No new avalanches have been reported since Wednesday. A natural avalanche cycle had occurred during the storm at the beginning of last week. 

Snowpack Summary

A melt-freeze crust is now expected to be capping the snowpack on all aspects to at least 1500 m and on sun-exposed slopes into the alpine. On north aspects at higher elevations, the snow surface may still be dry and crust-free. In exposed terrain at higher elevations, the recent storm snow may be wind-affected and ongoing wind transport is expected due to moderate northerly winds over the weekend. 

A melt-freeze crust from mid-February can be found approximately 80 cm beneath the surface with some spotty surface hoar crystals above. Recent snowpack testing suggests the crust is bonding well to the surrounding snow in some areas. However, this MIN post from Thursday shows a weak bond to the crust in the Mt. Washington area. With several subsequent days of melt-freeze, the bond is assumed to have improved since this observation but it is worth investigating further before committing to avalanche terrain. A strong, well-settled middle and lower snowpack exist below the crust.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Problems

Wind Slabs

An icon showing Wind Slabs

Wind slab formation is expected to be ongoing on Sunday as we continue to expect moderate winds from the north. Dry snow was reported above 1500 m so wind transport should be expected above that elevation in wind-exposed terrain. 

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

An icon showing Loose Wet

With each subsequent day of melt-freeze conditions, loose wet avalanches will become less likely. However, extra caution is still recommended on steep sun-exposed slopes during the heat of the afternoon. Where the crust is breaking down or non-existent, loose wet avalanches will be more likely. 

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Cornices

An icon showing Cornices

Cornices were reported to have grown large during the recent storm. They could still pose a threat from above or below, and are expected to become weak when the sun is at its strongest.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Mar 6th, 2022 4:00PM