Avalanche Forecast

Issued: Mar 10th, 2020 4:00PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Storm Slabs.

Avalanche Canada cgarritty, Avalanche Canada

Start small as you assess the outcome of Tuesday's storm. Expect the new snow's depth and reactivity to increase as you gain elevation and move into wind-exposed terrain.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

Tuesday night: Cloudy with another round of snowfall bringing 10-15 cm of new snow. Moderate to strong west winds.

Wednesday: A mix of sun and cloud. New snow totals of up to 30 cm at upper elevations. Moderate northwest winds. Alpine high temperatures around -5.

Thursday: Mainly sunny with cloud increasing over the day. Light variable winds. Alpine high temperatures around -7.

Friday: Mainly cloudy. Light to moderate northeast winds. Alpine high temperatures around -7.

Avalanche Summary

We don't yet have reports of avalanche activity from Tuesday's storm, however he new snow that accumulated over variable surfaces on Tuesday is expected to remain reactive to human triggering over the near term. This hazard will likely be most pronounced around steeper slopes that saw more dramatic wind loading during and immediately after the storm.

Snowpack Summary

25-35 cm of new snow is expected to accumulate in the region by Wednesday morning. The new snow has buried a mix of surface hoar and melt-freeze crust that varies with elevation and aspect. A poor bond is anticipated at this interface and the new snow will likely remain sensitive to human triggering on Wednesday.

Just over 100 cm of snow now overlies a layer of surface hoar on north-facing aspects near and above treeline. This layer was found to be reactive in some recent snowpack tests. Large avalanches composed of new snow may have potential to cause isolated step down avalanche activity at this layer.

The remainder of the snowpack is well-settled. The snowpack depth varies from around 300 to 400 cm around 1200 to 1400 m and tapering rapidly with elevation, with no snow below 700 m.

Terrain and Travel

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Be carefull around freshly wind loaded features.
  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.
  • Use small low consequence slopes to test the bond of the new snow.

Problems

Storm Slabs

An icon showing Storm Slabs

25-35 cm of new snow is expected to accumulate by the end of the storm Wednesday morning. This snow will be settling into storm slabs on an array of surfaces that are unlikely to form a solid bond over the short term. Expect the problem to be most pronounced at high elevations and in wind loaded areas.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Mar 11th, 2020 5:00PM