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Avalanche Forecast

Mar 12th, 2021–Mar 13th, 2021
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: South Coast Inland.

Rising freezing levels and sunshine will increase the likelihood of avalanches in many areas. Avoid exposure to cornices and steep sun-exposed slopes.

Confidence

Moderate - Uncertainty is due to difficult to forecast freezing levels. Recent weather patterns have resulted in a high degree of snowpack variability within the region.

Weather Forecast

FRIDAY NIGHT - Mainly cloudy with clear periods / light to moderate southwest wind / alpine low temperature near -2 / freezing level 1300 m 

SATURDAY - Mainly sunny / moderate southwest wind / alpine high temperature near 3 in the south, -1 in the north / freezing level 2500 m in the south, 2000 m in the north

SUNDAY - Mainly sunny with increasing cloud and a chance of flurries in the afternoon / alpine high temperature near 1 in the south, -2 in the north / freezing level 2300 m in the south, 1700 m in the north

MONDAY - A mix of sun and cloud / light variable wind / alpine high temperature near -3 / freezing level 1500 m

Avalanche Summary

Sunshine and rising freezing levels are expected to increase the likelihood of avalanches and cornice failures on Saturday. This trend is expected to be the most pronounced in the south of the region where freezing levels are expected to be higher than in the north.

On Thursday, there was a natural size 2.5 wind slab avalanche reported on a southwest aspect at 2200 m in the Duffey Lake area. There was also a natural size 2 cornice reported in the Coquihalla area.

Snowpack Summary

Wind slabs can be found on leeward slopes at upper elevations and may still be possible to trigger. Solar aspects likely have a crust on the surface, which may become moist/wet with exposure to sun and rising freezing levels. Soft, dry snow may be found in sheltered, shaded areas. Massive cornices exist on ridgelines, which can also act as triggers on slopes below. 

In the north of the region, a weak layer of facets buried in mid-February may still be found on north aspects near treeline but has been gaining strength. The lower snowpack is generally well settled and strong.

In the south of the region, the mid and lower snowpack is generally well consolidated with no concerns of buried weak layers. 

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.
  • Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet
  • A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
  • Minimize your exposure time below cornices.

Avalanche Problems

Loose Wet

Warm temperatures and sunshine are expected to create prime conditions for wet loose avalanches. Solar aspects will be the most likely trigger areas, but warm temperatures could potentially cause wet loose avalanches on all aspects, especially at lower elevations. 

This problem is expected to be most pronounced in the south of the region, however it is a concern in the north as well.

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

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 2

Cornices

Cornices weaken significantly when exposed to sun and warm temperatures. 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

Pay attention to the pattern of wind-drifting in the terrain where you are traveling and watch for cracking or changes in snow stiffness. Wind slabs are expected to be most prevalent in the north of the region.

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 2