Outflow incoming! Treeline probably has the most snow to transport, even if most of it has already been hit. Watch for small new wind slabs forming in unusual places as the arctic air invades.
Sunday's forecast outflow winds should find enough transportable snow to create a new wind slab problem in a reverse loading pattern (think southwest aspects instead of northeast). Winds should be strongest at lower elevations.
No new avalanches have been reported in the region. Observations have been limited, but the Yukon field team got a glimpse into treeline terrain Thursday and Friday with no avalanche activity to report.
Please share your own observations through the Mountain Information Network.
Roughly 20 to 30 cm of recent snow overlies the supportive early-December crust complex, which extends up to 1500 m. Much of it has blended into heavily wind-affected surfaces in exposed areas, but pockets of wind slab may still be found in leeward terrain around treeline. Previously sheltered north slopes will likely be impacted by outflow wind on Sunday.
A recent MIN report describes preserved surface hoar sitting on the crust in the Powder Valley. This setup is worth investigating throughout the region as slabs formed over this grain could be reactive.
Despite the presence of faceted grains in the lower snowpack, there are no layers of concern below the crust. Snowpack depths range from about 70 to 180 cm.
Saturday Night
Mainly cloudy with easing isolated flurries. 10 to 20 km/h south ridgetop wind shifting to northeast outflows in the morning and increasing. Treeline temperature -9 °C.
Sunday
A mix of sun and cloud. 20 to 30 km/h northeast outflow winds. Treeline temperature -13 °C.
Monday
A mix of sun and cloud with cloud diminishing. 10 to 15 km/h northeast or southeast ridgetop winds. Treeline temperature -14 °C.
Tuesday
Mainly sunny. 15 to 25 km/h east ridgetop wind. Treeline temperature -16 °C.
More details can be found in the Mountain Weather Forecast.
