Avalanche Forecast

Issued: Mar 23rd, 2021 4:00PM

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

Avalanche Canada MBender, Avalanche Canada

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New snow and wind forecast for Tuesday night through Wednesday morning will form fresh wind slabs at upper elevations.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

TUESDAY Night: Mainly cloudy with periods of snow, accumulation 5-15 cm, moderate west wind, treeline temperatures around -5 C, freezing level 800 m.

WEDNESDAY: Cloudy with flurries bringing 5-10 cm of new snow through the morning, moderate to strong southwest wind, treeline temperatures around -4 C, freezing level 1500 m.

THURSDAY: Mix of sun and cloud, light northwest wind, treeline temperatures around -3 C, freezing level 1600 m.

FRIDAY: Cloudy with sunny breaks, moderate northwest wind, treeline temperatures around -4 C, freezing level 1500 m.

Avalanche Summary

Reports on Monday showed several size 1.5-2 cornice releases with explosive control, as well as a few thin storm and wind slab avalanches to size 1.5 in the alpine. Loose wet and loose dry size 1 avalanches from steep terrain facing the sun were also reported in the afternoon.

Expect to see an increase in wind slab and possibly storm slab activity Wednesday with new snow and wind arriving Tuesday night.

Snowpack Summary

By Wednesday midday there may be anywhere from 10-20 cm of new snow from Tuesday night that has likely been redistributed by west and northwest winds. This adds to about 30+ cm accumulation from last weekend. All of the new snow sits above a widespread crust, with the exception of high north-facing terrain. Observations suggest the snow has bonded well to these old interfaces. There are currently no concerning weak layers in the snowpack, although a spotty early season facet layer deep in the snowpack could return as a problem later in the season.

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 careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • Be alert to conditions that change throughout the day.
  • Be alert to conditions that change with elevation and sun exposure.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Problems

Wind Slabs

An icon showing Wind Slabs

New snow combined with wind Tuesday night and through Monday morning will build fresh reactive wind slabs in open terrain.

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

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 24th, 2021 4:00PM