Avalanche Forecast

Issued: Mar 19th, 2021 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 shorton, Avalanche Canada

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Human triggered avalanches will be a concern on steep slopes where recent snow has accumulated. Gather information in simple terrain before considering more serious avalanche terrain.

Summary

Confidence

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

Weather Forecast

Stormy weather eases on Saturday morning before the next storm arrives on Sunday morning.

FRIDAY NIGHT: Scattered flurries with 15-20 cm of new snow, 30-50 km/h south wind, treeline temperatures around -2 C.

SATURDAY: Flurries end in the early morning hours the a mix of sun and cloud during the day, 10 to 20 km/h southwest wind, treeline temperatures around -2 C, freezing level steady around 800 m.

SUNDAY: Heavy snowfall starting in the morning with 20-30 cm by the evening, 40-60 km/h south wind, treeline temperatures around -4 C.

MONDAY: Another 20 cm of snow by the morning then sunny in the afternoon, 30-40 km/h west wind, treeline temperatures around -2 C.

Avalanche Summary

Storm slabs will grow rapidly over Friday night, and then gradually strengthen throughout the day on Saturday. Their reactivity will depend on how much snow has accumulated on a given slope, what time it stopped snowing, and whether there has been additional wind loading.

Snowpack Summary

New snow amounts between Thursday and Saturday morning are expected to total 30-50 cm, with amounts increasing dramatically with elevation. The snow is should strengthen relatively quickly when storm ends, however human triggered slabs are still a concern and it will be important to carefully monitor the reactivity of the storm snow through the day. North facing slopes likely have thicker slabs due to wind loading.

Along ridgelines, cornices are large and always have the potential of failing or being triggered from the weight of a human.

Terrain and Travel

  • Don't be too cavalier with decision making, storm slabs may remain sensitive to human triggering.
  • Be carefull around freshly wind loaded features.
  • Closely monitor how the new snow is bonding to the old surface.
  • Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.

Problems

Storm Slabs

An icon showing Storm Slabs

30-50 cm of recent snow has likely formed storm slabs on steep and wind loaded slopes. While these slabs are expected to strengthen quickly, they may still be reactive to human triggering on Saturday.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Valid until: Mar 20th, 2021 4:00PM