Avalanche Forecast

Issued: Mar 12th, 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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Another 20 to 40 cm new snow combined with strong southwest wind will continue to form touchy storm slabs and wind slabs. The avalanche danger will continue to increase throughout the day. A good day to stick to mellow terrain without overhead hazard!

Summary

Confidence

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

Weather Forecast

FRIDAY NIGHT: Cloudy, 10 to 20 cm new snow, 60 km/h southwest wind, alpine low -5 C, freezing level rising to 1300 m. 

SATURDAY: Cloudy, 10 to 20 cm new snow, 80 km/h southwest wind, alpine high +2 C, freezing level 1500 m.

SUNDAY: Mostly cloudy, 10 to 20 cm new snow, 30 km/h westerly wind, alpine high -5 C, freezing level at valley bottom.

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

Avalanche Summary

No new avalanches were observed on Friday at the time of writing. Looking ahead, newly formed storm slabs and wind slabs will be the primary concern on Saturday. 

Snowpack Summary

The storm brought around 20 cm new snow on Friday and more snow is in the forecast. 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

  • Storm slab size and sensitivity to triggering will likely increase through the day.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • 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

Friday's storm brought 20 cm of new snow. Another 10 to 20 cm overnight and 10 to 20 cm during the day on Saturday will continue to form reactive storm slabs. 

Strong to extreme southwest wind will redistribute the new snow and develop wind slabs in lee terrain features in the alpine and at treeline. The strong wind may form wind slabs lower down on lee slopes. The wind will contribute to cornice growth and the additional load may lead to cornice failures.

The freezing level is forecast to rise to 1500 m during the day. The storm might keep temperatures low. However, in areas with 0 C or warmer temperatures loose wet avalanches and cornice failures may be expected.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely - Almost Certain

Expected Size

1.5 - 2.5

Valid until: Mar 13th, 2021 4:00PM