Avalanche Forecast

Issued: Dec 16th, 2020 4:00PM

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

Avalanche Canada kdevine, Avalanche Canada

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Continued flurries and moderate to strong southwest winds will likely form new wind slabs that may be reactive to human triggers. Seek out sheltered terrain where possible, and avoid freshly wind loaded features.

Summary

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

WEDNESDAY NIGHT - Cloudy with clear periods and isolated flurries / southwest wind, 20-40 km/h / alpine low temperature near -13

THURSDAY - Flurries, up to 5 cm / southwest wind, 40-60 km/h / alpine high temperature near -11

FRIDAY - Flurries, 5-10 cm / southeast wind, 15-30 km/h / alpine high temperature near -7

SATURDAY - Flurries, 5-10 cm / southeast wind, 30-50 km/h / alpine high temperature near -6

Avalanche Summary

There have been no recent reports of avalanches in the region.

The most likely place to trigger an avalanche given current conditions would be on the leeward side of a ridgeline. 

Snowpack Summary

Continued flurries should help to maintain fresh, soft snow in sheltered terrain. Moderate to strong southwest winds will mean that wind slabs are likely to be found in the alpine and exposed treeline areas. 

Below this surface snow lies a widespread melt-freeze crust. The crust has been reported up to 1400 m in the Wheaton Valley, up to 1800 m near the Alaska border, but was not evident between 1400-1700 m in the Tutshi area. The main concern is newly-formed wind slabs sitting on this crust.

The lower snowpack is generally settled and strong after a massive storm at the beginning of December. However, there is potential for weak snow at the bottom of the snowpack in colder drier areas such as the Wheaton Valley. 

Snowpack depths range from around 150-170 in the White Pass area, to around 100 cm in drier areas such as Atlin and the Wheaton Valley.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Problems

Wind Slabs

An icon showing Wind Slabs

Moderate to strong southwest winds with additional new snow will continue to create fresh wind slabs. 

Previous northerly winds mean that there may still be some wind slabs on southerly aspects.

Assess all aspects for potential wind slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 17th, 2020 4:00PM