Avalanche Forecast
Issued: Mar 12th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
cgarritty,
Avalanche Canada
Strong outflow winds push into the region on Friday - strongest at low elevations. Higher elevations still hold recent and reactive slabs, but watch for touchy new wind slabs forming in atypical elevation bands and aspects over the day.
Summary
Confidence
High -
Weather Forecast
Thursday: Mainly sunny with cloud increasing in the afternoon. Light northwest winds shifting northeast and increasing.
Friday: Mainly cloudy. Moderate to strong northeast winds. Alpine temperatures dropping to around -15.
Saturday: A mix of sun and cloud. Moderate to strong northeast winds easing over the day. Alpine high temperatures around -17.
Sunday: Sunny. Light northeast winds. Alpine high temperatures around -9.
Avalanche Summary
Reports from the Whistler area on Wednesday showed numerous small (up to size 1.5) storm slabs releasing with skier traffic as well as ski cutting.Â
Snowfall totals were variable over the region. Widespread strong to extreme winds formed wind slabs up to 20 cm deep in areas with 10 cm of new snow, with places with up to 30 cm of new snow forming slabs up to 80 cm deep. Recent wind slab formations may remain reactive to human triggering on Friday.
Snowpack Summary
10-30 cm of new snow fell in the region during Tuesday's storm, with the greatest amounts found at higher elevations and toward the south of the region. Strong to extreme winds were a notable feature of the storm. The new snow - wind-affected at higher elevations - has buried variable surfaces that include surface hoar in sheltered areas, sun crusts on southerly slopes, and yet more wind-affected surfaces in exposed areas.
Some professionals in the region are still tracking a weak layer of surface hoar crystals and/or faceted grains currently found around 100 cm deep on northerly aspects at treeline and lower alpine elevations. The distribution of this layer is spotty, likely existing as a problem only in isolated steep, sheltered, north-facing slopes at mid elevations.
Weak faceted snow and melt-freeze crusts exist near the base of the snowpack in some of the region, particularly the eastern and northern parts. This layer is considered dormant, as it hasn't produced an avalanche since February 20th. This layer may require a very large load, such as a cornice fall, or rapid weather changes to reactivate.
Terrain and Travel
- Be carefull around freshly wind loaded features.
- Watch for avalanche hazard to increase throughout the day.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Wind Slabs
Reactive wind slabs continue to be reported at higher elevations. Recent slabs won't have much time to stabilize before Friday's switch to northeast winds begins to reverse-load loose snow into new slabs over previously scoured surfaces. Keep your guard up in exposed lower elevations, strong outflow winds may form slabs over a buried layer of surface hoar.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 13th, 2020 5:00PM
