Avalanche Forecast
Regions: Flathead, Lizard, Lizard-Flathead.
Rising temperatures are creating very dangerous avalanche conditions and terrible riding quality. No reason to go near avalanche terrain.
Confidence
Moderate
Avalanche Summary
Several natural and artificially triggered size 1 to 2 storm slab avalanches have occurred daily since Thursday.
This rider-triggered slab from Saturday looks like it could have run on a persistent weak layer in the upper snowpack. Glad everyone got out okay!
Looking forward, we can expect an uptick in these types of avalanche activity as temperatures rise.
Snowpack Summary
The upper snowpack remains warm and wet after having been soaked by rain at most elevations.
A melt-freeze crust is found around 60 cm deep, except on high-elevation north and east-facing slopes.
A surface hoar or facet layer from late January is buried 100 to 150 cm deep on north and east aspects at treeline and above. This may re-emerge as a persistent slab problem with warming this week.
Weather Summary
Monday night
Cloudy with 1-5 cm of snow above 2000 m, light rain below. 30 to 50 km/h southwest ridgetop winds. Treeline temperature 0 °C. Freezing level 2200 m.
Tuesday
Flurries bringing a trace of snow. 20 to 30 km/h southwest ridgetop winds. Treeline temperature +5 °C. Freezing level rising to 2600 m.
Wednesday
Sunny. 10 to 20 km/h south ridgetop winds. Treeline temperature +10 °C. Freezing level rising to 3500 m.
Thursday
Flurries. 30 to 40 km/h southwest ridgetop winds. Treeline temperature +1 °C. Freezing level falling to 2000 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be aware of the potential for large avalanches due to buried weak layers.
- Avoid exposure to overhead avalanche terrain; avalanches may run surprisingly far.
- Only the most simple non-avalanche terrain with no overhead hazard is appropriate at this time.
Avalanche Problems
Loose Wet
A wet upper snowpack is primed for loose wet avalanches as temperatures continue to rise.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1 - 2
Storm Slabs
Heavy, wet storm slabs will likely be reactive as temperatures rise.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1 - 2
Persistent Slabs
A persistent weak layer of surface hoar or facets is buried 80 to 150 cm deep. This layer will likely become increasingly active in the coming days as the snowpack warms and weakens.
Aspects: North, North East, East, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 2 - 3