Avalanche Forecast
Regions: Northwest Coastal.
This forecast lacks field observations and has lots of uncertainty. This will be the last avalanche forecast of the season. Reactive storm slabs remain the primary concern, especially around ridge features and wind loaded terrain.
Confidence
Low - Uncertainty is due to the limited number of field observations.
Weather Forecast
Saturday night: Flurries and snow, 5-10 cm. Alpine low temperature -7 C.Moderate south-southwest wind.
Sunday: Flurries and snow, 5-15 cm. Alpine high temperature -4 C. Moderate south wind.
Monday: Cloudy with scattered flurries, up to 10 cm. Alpine high temperature -10 C. Light to moderate east wind.
Tuesday: Mostly cloudy. Alpine high temperature -10 C. Light east wind.
Avalanche Summary
A large (size 2.5) natural glide slab release was observed on Tuesday. The debris from the release overran the John Little Falls hiking trail. Natural glide slab activity has been a regular occurrence during recent periods of daytime warming, reinforcing the importance of avoiding glide cracks and areas exposed glide slab hazards.
There are very limited field observations at this time and no recent avalanches have been reported.
Snowpack Summary
Upwards of 10-30 cm of snow has accumulated around the region over the past few days, along with a steady westerly wind. This covers a variety of wind-affected surfaces and a melt freeze crust on south aspects and slopes below 1100 m.
A layer of surface hoar crystals is buried around 30-60 cm in sheltered areas at and below treeline, shallow enough for human triggering on steep slopes where it is preserved. Recent observations of this layer are lacking.
An early-season layer of faceted grains and a melt-freeze crust can likely be found near the base of the snowpack at high elevations. A large load, such as a large cornice fall, may have potential to trigger it.
Terrain and Travel
- Storm slab size and sensitivity to triggering will likely increase through the day.
Avalanche Problems
Storm Slabs
Flurries falling with steady winds will build increasingly reactive storm slabs. The most reactive deposits will be around ridgetop and in wind-loaded areas.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 2
Persistent Slabs
A weak layer of surface hoar crystals is buried around 30 to 60 cm deep in sheltered, shady terrain around treeline. It was reactive to both human and natural triggers last week and there is uncertainty about whether it is still a problem.
Aspects: North, North East, East, West, North West.
Elevations: Treeline.
Likelihood: Unlikely - Possible
Expected Size: 1.5 - 2.5