Avalanche Forecast
Regions: Lizard-Flathead.
A storm will start to build new slabs and load buried weak layers. Time to dial the terrain choices back and adopt a conservative mindset this weekend.
Confidence
Moderate - Forecast precipitation (either snow or rain) amounts are uncertain.
Weather Forecast
FRIDAY NIGHT: Cloudy with snowfall, accumulation 10 to 15 cm, 40 km/h southwest wind, alpine temperature -5 C, freezing level rising to 1400 m.
SATURDAY: Cloudy with snowfall, accumulation 10 cm, 40 km/h southwest wind, alpine temperature -5 C, freezing level 1400 m.
SUNDAY: Cloudy with snowfall, accumulation 30 to 50 cm, 50 km/h southwest wind, alpine temperature -4 C, freezing level 1500 m.
MONDAY: Partly cloudy with afternoon snowfall, accumulation 5 cm, 20 km/h southwest wind, alpine temperature -5 C.
Avalanche Summary
Recently, a few small storm and wind slab avalanches were triggered by explosives out of steep northerly terrain at treeline and lower alpine elevations.
Avalanche activity is expected to increase over the weekend during the stormy period. Riders could trigger storm or wind slabs and there remains a possibility of triggering deeper weak layers, which would result in destructive avalanches.
Snowpack Summary
Upwards of 20 cm of snow is forecast to accumulate in the region by Saturday afternoon. The snow will be accompanied by a rise in freezing level and strong southwest wind. Storm slabs are expected to build in sheltered terrain and wind slabs in exposed terrain at higher elevations.
In the Lizard Range, a melt-freeze crust has been reported around 20 to 40 cm deep and up to an elevation of 1900 m. A few reports suggest that sugary faceted grains may exist around the crust but others indicate no weakness. It remains to be seen if this layer will become an avalanche problem.
Around 50 to 100 cm deep, weak layers of feathery surface hoar and/or faceted grains may overly a hard melt-freeze crust. These layer appears to be bonding in certain areas of the region but remain suspect where they exist.
Terrain and Travel
- Watch for fresh storm slabs building throughout the day.
- Approach lee and cross-loaded slopes with caution.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Avalanche Problems
Storm Slabs
Snow will accumulate over the day, producing storm slabs in sheltered terrain and wind slabs in exposed terrain. Use particular caution if you find more than 20 cm of snow accumulate and step out of avalanche terrain during periods of rapid snow accumulation (i.e., 2+ cm of snow an hour).
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 2
Persistent Slabs
Weak layers of feathery surface hoar and/or sugary faceted grains may be found above a hard melt-freeze crust around 50 to 100 cm deep. Although avalanche activity hasn't been reported on these weak layers for over a week, the likelihood of triggering them may increase during this stormy period.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1.5 - 3