Avalanche Forecast

Issued: Mar 22nd, 2020 4:00PM

The alpine rating is low, the treeline rating is low, and the below treeline rating is low. Known problems include Persistent Slabs.

Avalanche Canada ahanna, Avalanche Canada

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Minor accumulations of new snow may form isolated slabs in the most wind exposed alpine terrain. Loose dry avalanches are most likely where new snow sits over a crust.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

Sunday night: Up to 5 cm new snow. Light northeast wind. Freezing level 700 m.

Monday: 5-10 cm new snow. Light northeast wind. Freezing level 900 m.

Tuesday: Up to 5 cm new snow then clearing. Moderate northeast wind. Freezing level 500 m.

Wednesday: Clear. Moderate northeast wind. Freezing level 1000 m.

Avalanche Summary

Loose wet avalanches were observed on solar aspects during the warm, sunny week. A few cornice failures were observed last Wednesday but did not trigger slabs.

If you decide to travel in the backcountry, consider sharing your observations with us and fellow recreationists via the Mountain Information Network (MIN) to supplement our data stream as operators are shutting down. Even just a photo of what the day looked like would be helpful.

Snowpack Summary

Up to 20 cm of new snow sits over melt-freeze crusts on solar aspects, and extensively wind affected surfaces in exposed terrain that did not see the sun. 

A weak layer of surface hoar crystals buried early March may be found around 30-50 cm deep.

An early-season layer of faceted grains and melt-freeze crust near the base of the snowpack may linger. The most suspect locations to trigger this layer would be where the snowpack is thin near rocky outcrops. A large load, such as a cornice fall, also has the potential of triggering it. With cooling temperatures and increased cloud cover over the next few days, deep persistent avalanches on these layers are unlikely.

Terrain and Travel

  • Closely monitor how the new snow is bonding to the crust.
  • Keep in mind the crust offers an excellent bed surface for avalanches.
  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
  • Avalanche hazard may have improved, but be mindful that deep instabilities are still present.

Problems

Persistent Slabs

An icon showing Persistent Slabs

A weak layer of surface hoar crystals is buried around 30 to 50 cm in sheltered, shady terrain around treeline. Recent warm temperatures have likely promoted bonding of this layer and there is uncertainty around whether it is still sensitive to triggering.

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

Elevations: Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Mar 23rd, 2020 5:00PM

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