Avalanche Forecast

Issued: Mar 12th, 2021 4:00PM

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

Avalanche Canada kdevine, Avalanche Canada

Email

Rising freezing levels and sunshine will increase the likelihood of avalanches and cornice failures. Pay close attention to temperatures and minimize exposure to cornices and steep, sun-exposed slopes during the heat of the day.

Summary

Confidence

Moderate - Uncertainty is due to difficult to forecast freezing levels.

Weather Forecast

FRIDAY NIGHT - Mainly cloudy / light to moderate southwest wind / alpine low temperature near -1 

SATURDAY - Mainly cloudy, clearing in the morning, and then mainly sunny / moderate southwest wind / alpine high temperature near 0 / freezing level 2000 m

SUNDAY - Flurries, 10-15 cm / strong south wind / alpine high temperature near -2 / freezing level 1500 m

MONDAY - A mix of sun and cloud / light variable wind / alpine high temperature near -4 / freezing level 1500 m

Avalanche Summary

Rising freezing levels and sunshine will increase the likelihood of avalanches and cornice failures on Saturday.

On Thursday, there was a report of a human-triggered size 2.5 wind slab avalanche on a southwest aspect at 2300 m, in extreme terrain. 

There have been reports most days this week of a few natural and/or human-triggered wind slab and dry loose avalanches, ranging between size 1-2, as well as natural size 1 loose wet avalanches on solar aspects at lower elevations.

Snowpack Summary

Wind slabs can be found on leeward slopes at upper elevations and remain possible to trigger. Solar aspects have a crust on the surface, that may become moist with rising freezing levels and direct sun. Soft, dry snow can be found in sheltered, shaded areas. 

Massive cornices exist on ridgelines, which can act as triggers on slopes below. 

The mid and lower snowpack is well settled and strong in most areas. A weak layer of facets buried in mid-February may still be found but has been gaining strength.

Terrain and Travel

  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
  • Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.
  • Back off slopes as the surface becomes moist or wet with rising temperatures.
  • Minimize your exposure time below cornices.

Problems

Cornices

An icon showing Cornices

Cornices begin to weaken when exposed to warm temperatures and intense sun. When they fail, they can have enough mass to be very destructive, and they can also trigger slab avalanches on the slopes below them. 

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Wind Slabs

An icon showing Wind Slabs

Pay attention to the pattern of wind-drifting in the terrain where you are traveling and watch for cracking or changes in snow stiffness. 

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

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