Avalanche Forecast
Regions: Flathead, Lizard, Lizard-Flathead.
Further heavy snowfall is expected overnight Sunday.
Avoid exposure to avalanche terrain as storm snow needs time to stabilize and persistent weak layers may be reactive to human triggers.
Confidence
Moderate
Avalanche Summary
On Sunday explosive control produced avalanches up to size 2 in the recent storm snow and on buried weak layers. Natural avalanches were observed on the persistent weak layers to size 2.5 from steep terrain features.
Activity is expected to continue with heavy snowfall Sunday night.
Snowpack Summary
By Monday morning storm totals are expected to reach up to 60 cm in the Lizard Range, and around 40 cm elsewhere. Moderate to strong southwest winds have likely redistributed this snow into deeper deposits at treeline and above. Lower elevations have received mostly rain, creating wet surface conditions or a crust.
A persistent weak layer of surface hoar or facets from late January is buried 70 to 100 cm deep. This layer is expected to be more reactive with the warming temperatures and new snow/ rain. The mid and lower snowpack is generally well settled.
Weather Summary
Sunday Night
Mostly cloudy with 15-20 cm of snow. Snowfall is expected to begin the night at 1500 m, and drop to 500 m by morning. Winds increase overnight to 50 km/h southwest at ridgetop.
Monday
Mostly clear skies. Southwest ridgetop wind eases to 25 km/h at ridgetop. Treeline temperature -3 °C. Freezing level rising to 1700 m.
Tuesday
Cloudy with up to 15 cm of snow. 30 to 40 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level rising to 1600 m.
Wednesday
Clearing skies with 20 to 30 km/h southwest ridgetop wind. Freezing levels rise to 2000 m, with treeline temperatures around 0 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
- Avoid the runout zones of avalanche paths. Avalanches could run full path.
- Even brief periods of direct sun could produce natural avalanches.
Avalanche Problems
Storm Slabs
Storm slabs are expected to remain very sensitive to triggers, and will likely produce natural avalanches as storm snow continues to accumulate overnight on Sunday. Deeper and more reactive deposits have likely formed near ridgelines.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 2.5
Persistent Slabs
Heavy snowfall and warm temperatures will stress buried weak layers. Small avalanches have potential to step down and produce very large avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 2 - 3