Avalanche Forecast

FRIDAY NIGHT: Cloudy skies, no significant precipitation, moderate wind from the southwest, treeline temperatures around -5 C.

SATURDAY: Cloudy with flurries starting in the late morning and bringing 5-15 cm of snow by the evening (with the greatest accumulations in the eastern part of the region), moderate wind from the southwest, treeline temperatures around -5 C.

SUNDAY: Another 5-10 cm of snow by the morning then clearing throughout the day, light wind from the northwest, treeline temperatures drop to -8 C throughout the day.

MONDAY: Mix of sun and cloud, light wind from the northeast, treeline temperatures around -12 C.

There have been regular reports of small (size 1) human-triggered wind slabs along ridgetops over the past few days. With the incoming storm we could expect to see larger wind slabs form at upper elevations. 

Last week there were several large (size 2-3) persistent slab avalanches reported on the late January surface hoar layer, and this layer produced a few smaller (size 1) human-triggered slabs as recently as Tuesday. We could see the reactivity of this weak layer increase in areas where new snow accumulates this weekend.

New snow will form some isolated wind slabs at upper elevations and 5 to 15 cm of low density snow in sheltered terrain. Roughly 10 to 20 cm of snow sits above hard wind-affect snow and melt-freeze crusts in most terrain, except north-facing terrain at treeline where there may still be soft snow. There are two layers of buried surface hoar in the upper snowpack: one was buried on Jan 30 and is 20 to 40 cm deep, the other was buried on Jan 14 and is 30 to 50 cm deep. These layers remain reactive in some snowpack tests and have resulted in some avalanche activity over the past week. Triggering avalanches on these layers has become less likely, but may still be possible on sheltered northerly slopes. The lower snowpack is well consolidated, with a crust/facet layer found 100 to 200 cm deep. This layer is currently considered dormant, but could become active later this season as discussed in this forecaster blog.

• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
• Use ridges or ribs to avoid areas of wind loaded snow.