Avalanche Forecast
Issued: Dec 18th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Storm Slabs and Deep Persistent Slabs.
Benjamin Firth,
A series of storms will enter the region over the next three days. The more snow and wind we receive the higher the avalanche danger. Avalanche control forecasted on 93N between Saturday and Tuesday afternoon. Check 511 for up to date information.
Summary
Weather Forecast
Fri night and Sat: Flurries. Accumulation: 16 cm. Alp tmp: High -6 C. Mostly light ridge wind occasionally gusting to 40 km/h. Freezing level: 1500 metres.
Sunday: Periods of snow. Accumulation: 16 cm. Alp tmp: Low -9 C, High -3 C. Mostly light ridge wind occasionally gusting to 40 km/h. Freezing level: 1700 metres.
Mon and Tues: Accumulation: 23 cm.
Snowpack Summary
SW winds and new snow will continue to build wind slabs in the alpine and open treeline. Possible surface hoar down 25cm in sheltered locations treeline and below. The midpack is generally supportive with a weaker base consisting of facets and some locations depth hoar. Average depth is 65cm - 160cm depending on region and elevation.
Avalanche Summary
Road patrol south today one recent size 2.5 avalanche was observed out of a East facing alpine feature in the Mount Wilson area otherwise nothing else observed. Visibility was to ridgetop. Over the last three days compression tests in the ice fields treeline and below produced no results.
Confidence
Intensity of incoming weather systems is uncertain on Friday
Problems
Wind Slabs
New snow and moderate to strong winds forming wind slabs on leeward and cross-loaded terrain features.
- Minimize overhead exposure during periods of heavy loading from new snow, wind.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Storm Slabs
New snow may create soft slabs and be reactive on the Dec 14th layer
- Carefully assess open slopes at and below treeline where buried surface hoar may be preserved.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
Be cautious of thick to thin snowpack areas being likely trigger locations. The new windslabs forming have the potential to step down to the weakness at the base of the snowpack.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
- Use caution in thin snowpack areas.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 19th, 2020 4:00PM
