Forecasted ridgetop winds will become moderate to strong from the SW on Friday. Watch for fresh wind-slabs in the alpine and exposed tree-line locations.
With stronger winds forecast for Friday and lots of snow available for transport, fresh and reactive wind slabs can be expected in the alpine and open areas near treeline.
Increased SW winds on Friday may result in dry loose avalanches out of steep alpine terrain. Avalanches likely will be small, but will be a concern if funneled into a terrain trap or gully.
The base of the snowpack consists of weak facets and depth hoar. There has not been much recent activity on this layer but forecasters are still warry of this problem. Use caution in steep terrain, large planar slopes, and thin areas where failures on these basal facets are more likely to propagate.
A road patrol on Highway 93 North in good visibility showed one size 1 wind slab on the east face of Mt Saskatchewan. Sunshine Village reported two natural wind-slabs (size 2) above Bourgeau Left and Right waterfalls. The slab on Bourgeau Right came over the waterfall.
The ski-hills reported several explosive triggered wind-slabs in the alpine.
10-20 cm recent storm snow and increased winds on Friday will create fresh wind-slabs at treeline and above. 30-50 cm overlies the Dec. 31 surface hoar/sun crust. Below this, in the mid-pack, two crusts (Dec. 22 and Dec. 5) exist as high as 2350m and have been providing the primary support for skiing. The base of the snowpack remains weak with depth hoar and facets.
Friday will bring increasing cloudiness with light snow in the afternoon. Ridgetop winds will be from the SW and increase through the day to mod-strong. Valley bottom temperatures will rise to -13.
Saturday will bring scattered flurries and mod to strong SW winds. Valley bottom temperatures will rise to around -8.
For more information, click here for the Mountain Weather Forecast.
