Avalanche Forecast

Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.

Thursday night: Mostly clear, light northwest winds, alpine temperatures dropping to -20 C.

Friday: Mainly sunny, light northwest winds, alpine high temperatures near -14 C. 

Saturday: Partly cloudy, light variable winds, alpine high temperatures near -15 C.

Sunday: Increasing cloud, light south winds, alpine high temperatures near -12 C.

Recent strong winds have formed wind slabs in lee features at upper elevations that may be possible to human trigger. With the strong winds on Tuesday, operators in the region reported small to large (size 1-2) wind slabs releasing naturally as well as several size 1-2 explosive-triggered cornices. 

On Monday and Tuesday, several operators in the region reported small (size 1-1.5) human-triggered avalanches releasing on a weak layer of surface hoar on north, east and southeast aspects at treeline and below treeline elevations. These avalanches were breaking 25-45 cm deep. 

Recent winds have scoured snow surfaces, loaded cornices, and formed stiff wind slabs in alpine and upper treeline areas. These wind slabs sit over a variety of surfaces, including isolated surface hoar, sun crusts, and settling storm snow. A new sun crust may be forming on steep solar aspects, and there here have been reports of surface hoar growing on the snow surface.  

50-70 cm of snow from the past week has buried a weak of layer of surface hoar that is likely to be preserved in sheltered, open slopes at and below treeline. Observers in the south of the region continue to report sudden results in the snowpack tests and shooting cracks on this layer. Don't let benign weather lure you into complacency. Recent avalanche activity demonstrates that this layer is likely to be reactive where it is preserved and that it warrants careful assessment. Below 1700 m, 20-30 cm of snow is settling above a decomposing melt freeze crust. 

Deeper in the snowpack, a couple of older persistent weak layers may still be identifiable from late and early December, consisting of surface hoar and a crust with faceted snow and buried anywhere from 100-200 cm deep. Prolonged periods of inactivity and unreactive snowpack test results suggest that these layers have trended towards dormancy. 

• Carefully evaluate steep lines for wind slabs.
• Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
• Avoid exposure to slopes that have cornices overhead.