Avalanche Forecast
Regions: South Rockies.
New slabs will form as the storm arrives. A conservative mindset should be adopted this weekend as slabs build and weak layers are loaded.
Confidence
Moderate - Forecast precipitation (either snow or rain) amounts are uncertain.
Weather Forecast
FRIDAY NIGHT: Cloudy with snowfall, accumulation 5 cm, 40 to 80 km/h southwest wind, alpine temperature -5 C, freezing level 1300 m.
SATURDAY: Cloudy with snowfall, accumulation 5 to 10 cm, 40 to 80 km/h southwest wind, alpine temperature -5 C, freezing level 1400 m.
SUNDAY: Cloudy with snowfall, accumulation 20 to 40 cm, 40 to 80 km/h southwest wind, alpine temperature -4 C, freezing level 1700 m.
MONDAY: Partly cloudy with afternoon snowfall, accumulation 5 cm, 20 km/h southwest wind, alpine temperature -5 C.
Avalanche Summary
No recent avalanches have been reported in the region. 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
Around 10 to 15 cm of snow is forecast to accumulate by Saturday afternoon with associated strong southwest wind. New storm slabs may form in sheltered terrain and wind slabs in exposed terrain features.
Weak layers of feather surface hoar and/or sugary faceted grains may be found above a hard melt-freeze crust around 50 to 100 cm deep. The most recent avalanche activity on these layers were reported on December 23 and 25.
The base of the snowpack consists of faceted grains and a hard melt-freeze crust from early-November. The most recent activity on this layer was on December 23.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Avoid slopes that sound hollow or drum-like.
- Be aware of the potential for large avalanches due to the presence of buried weak layers.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Avalanche Problems
Wind Slabs
Some new snow, strong southwest wind, and an increasing freezing level are forecast, which will likely form new wind slab adjacent to ridges, particularly in alpine terrain. A conservative mindset should be applied on Saturday as these slabs build.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 2
Persistent Slabs
A hard melt-freeze crust is found around 50 to 100 cm deep. The concern is where weak layers of surface hoar and/or faceted grains exist above the crust. For areas where either of these weak layers exists above the crust, the possibility remains that riders could trigger large avalanches. The potential of triggering these layers will increase during this weekend's stormy period.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Unlikely - Possible
Expected Size: 1.5 - 3