Avalanche Forecast

Issued: Mar 21st, 2021 4:00PM

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

Avalanche Canada shorton, Avalanche Canada

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Keep your guard up on steep and open slopes, as there is now enough fresh snow for human triggered avalanches.

Summary

Confidence

Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.

Weather Forecast

Unsettled weather will bring a mix of sun, cloud, and light flurries for the next few days.

SUNDAY NIGHT: Scattered flurries bring up to 10 cm of snow in the north of the region and 10-20 cm in the south, 30-50 km/h southwest wind, treeline temperatures drop to -6 C.

MONDAY: Clearing skies in the north while the south remains cloudy with isolated flurries, 20-30 km/h northwest wind, treeline temperatures around -5 C.

TUESDAY: Mix of sun and cloud, light west wind, treeline temperatures around -5 C.

WEDNESDAY: Cloudy with isolated flurries bringing up to 5 cm of new snow, 30-50 km/h southwest wind, freezing level climbing to 1600 m with treeline temperatures around -2 C.

Avalanche Summary

Field reports from Saturday suggest the new snow was starting to show signs of slab development in the afternoon, with a few reports of small (size 1) wind slab avalanches in alpine terrain. The addition of more snow on Sunday will likely form more widespread slabs, with the greatest concern on wind loaded slopes.

Snowpack Summary

On Monday there will be 15 cm of new snow in most parts of the region, while the Coquihalla may have closer to 25 cm. This will bring recent snowfall totals to 20-40 cm and perhaps tip the scales to finally see storm slab development. This recent snow overlies a widespread melt-freeze crust, with the exception of high elevation northerly aspects. The lower snowpack is strong and settled.

Remember that cornices along ridgelines are large at this time of year and always have the possibility of failing naturally or from the weight of a human.

Terrain and Travel

  • Be carefull around freshly wind loaded features.
  • Dial back your terrain choices if you are seeing more than 20 cm of new snow.
  • If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.
  • 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

Recent storm totals will have reached 20-40 cm by Monday morning, which means there is potential for storm slabs on steep open slopes, however the most likely place to trigger an avalanche will be on wind loaded slopes at upper elevations.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Cornices

An icon showing Cornices

Cornices are large and looming along many ridgelines, and have likely grown with the recent snow and wind. 

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Mar 22nd, 2021 4:00PM

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