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Avalanche Forecast

Feb 26th, 2020–Feb 27th, 2020
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
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
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.

Wind loaded pockets of snow may sit on a weak interface. Caution around wind loaded ridgetops in the alpine and on convexities at upper treeline elevations.

Confidence

Moderate - Uncertainty is due to the extreme variability of wind effect on the snowpack.

Weather Forecast

Wednesday night: Scattered flurries bringing a trace of new snow. Moderate southwest wind. Freezing level 1100 m.

Thursday: Scattered flurries bringing a trace of new snow. Moderate southwest wind. Freezing level 1400 m.

Friday: Mix of sun and cloud. Light to moderate southwest wind. Freezing level 1600 m in the north, 2000 m in the south.

Saturday: Around 5 cm new snow. Light to moderate southwest wind. Freezing level 1400 m.

Avalanche Summary

Some minor snowballing observed on steep sunny slopes Wednesday. A few skier controlled wind slabs up to size 1.5 were reported Tuesday. Natural and skier triggered wind slab avalanches were observed on northeast to west aspects in the alpine size 1.5-2 on Monday. We have not received reports of avalanche activity in the south of the region.

Snowpack Summary

15-30 cm of recent snow, and as high as 50 cm in the Coquihalla, may overly isolated patches of surface hoar in sheltered areas or sun crusts on solar aspects. Wind slab formation has been variable through the region. Extensive wind slab development has been reported in the western reaches of the region, and is suspected in the Coquihalla. In the northeast of the region, wind loading may be isolated to soft slabs in immediate lees in the alpine.

In the north part of the region (ie. Duffey/Hurley/Goldbridge), a deep instability exists at the base of the snowpack. It has not produced recent avalanche activity, with the most recent event on February 17. Rapid warming or heavy loading by new snow/wind/rain events 

Terrain and Travel

  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • Brief periods of sun could quickly initiate natural avalanche activity.
  • Surface hoar distribution is highly variable. Avoid generalizing your observations.
  • Investigate the bond of the recent snow before committing to your line.

Avalanche Problems

Wind Slabs

Wind effect has been variable through the region. In the northeast of the region, wind loading may be isolated to soft slabs in immediate lees in the alpine. More extensive wind slab development has been reported in the western reaches of the region, and is suspected in the Coquihalla. Wind slabs may sit over a weak interface, particularly around treeline.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2

Deep Persistent Slabs

In the north of the region (e.g. Duffey, Hurley, Goldbridge), a buried weak layer lingers at the base of the snowpack. This layer has been quiet, with no reports of avalanches on it since mid February. There is potential for it to wake up with rapid warming or significant loading by new snow.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely

Expected Size: 2.5 - 3.5