Avalanche Forecast

Issued: Mar 13th, 2021 4:00PM

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

Avalanche Canada ldreier, Avalanche Canada

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The ongoing storm will bring another 10 to 20 cm overnight and isolated flurries during the day. The snowpack will need time to stabilize. A good day to make conservative terrain choices and minimize overhead hazard!

Summary

Confidence

Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.

Weather Forecast

SATURDAY NIGHT: Cloudy, 10 to 20 cm new snow, 60 km/h southwest wind, alpine low -12 C, freezing level lowering to valley bottom.

SUNDAY: Mostly cloudy, trace of new snow, 40 km/h westerly wind, alpine high -11 C.

MONDAY: Mix of sun and cloud, trace of new snow, 30 km/h southwest wind, alpine high -5 C.

TUESDAY: Mostly sunny, up to 5 cm new snow, 30 km/h southwest wind, alpine high 0 C, freezing level rising to 1000 m.

Avalanche Summary

Several small natural wet loose avalanches of size 1 and a few small skier triggered wind slab avalanches (size 1) were reported on Friday.

Snowpack Summary

The ongoing storm brought up to 50 cm snow combined with strong to extreme southwest wind and more snow is in the forecast for tonight. The new snow may overly widespread wind affect at alpine elevations, feathery surface hoar on northerly aspects and in sheltered terrain features around treeline, or a melt-freeze crust on southerly aspects and below treeline.

There are presently no widespread deeper concerns. However, faceted snow at the base of the snowpack exists in much of the region and always has the potential of being triggered in shallow, rocky slopes.

Terrain and Travel

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
  • Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Problems

Storm Slabs

An icon showing Storm Slabs

The storm brought up to 50 cm new snow since Thursday and another 10 to 20 cm is forecast for tonight. Storm slabs will be reactive to human traffic, especially where it sits on surface hoar on northerly aspects and in sheltered terrain features around treeline or a melt-freeze crust on southerly aspects and below treeline.

Moderate westerly wind will continue to form fresh reactive wind slabs. Strong to extreme southwest wind redistributed the new snow and developed touchy wind slabs in lee terrain features in the alpine and at treeline. The strong wind may have formed wind slabs lower down on lee slopes than expected. The wind contributed to cornice growth and the additional load may lead to cornice failures.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1.5 - 2.5

Valid until: Mar 14th, 2021 4:00PM