Avalanche Forecast
Issued: Feb 23rd, 2020 4:00PM
The alpine rating is Storm Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeThe developing storm slabs are expected to be reactive to human triggers on Monday. Careful terrain selection and route finding will be required to effectively manage risk.
Summary
Confidence
Moderate - Uncertainty is due to how buried persistent weak layers will react with the forecast incoming weather.
Weather Forecast
SUNDAY NIGHT: Cloudy with flurries; 3-5 cm, light west wind, alpine temperature -7 C, freezing level below valley bottom.
MONDAY: Mostly cloudy with possible flurries; 0-3 cm, light west wind, alpine temperature -2 C, freezing level 1000 m
TUESDAY: Mix of sun and cloud, light to moderate south wind, alpine temperature -3 C, freezing level 800 m.
WEDNESDAY: Mix of sun and cloud, light to moderate southwest wind, alpine temperature 0 C, freezing level rising to 1300 m.
Avalanche Summary
Numerous size 2 storm slab avalanches were remotely skier triggered on Saturday. These slabs will become increasingly touchy and hazardous as the new snow stacks up and settles into a cohesive slab sitting on top of a fragile layer of surface hoar.
Snowpack Summary
20-35 cm of recent snow has buried a widespread layer of surface hoar (size 5-20 mm.). This layer exists at all elevations. This same layer of surface hoar has been reported as sitting on a thin sun crust on solar aspects which is a particularly nasty combination. The new snow will likely become increasingly reactive to human triggers as it stacks up and settles into a cohesive slab. The early February rain crust down 70-100 cm. is another prominent layer in the upper snowpack that requires monitoring. The mid and lower snowpack are generally well settled and strong.
Terrain and Travel
- Shooting cracks, whumphs and recent avalanches are strong indicators of an unstable snowpack.
- Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
- Be alert to conditions that change with elevation, aspect and exposure to wind.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Storm Slabs
20-30 cm of recent snow is sitting on top of a widespread layer of surface hoar at all elevations. On solar aspects the surface hoar is sitting on a crust, a particularly nasty combination.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 24th, 2020 5:00PM