Lizard-Flathead

Touchy storm slab continues to build amid ongoing flurries. Watch for signs of instability in the storm snow and caution around deep windloaded pockets in the alpine.

• Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
• Choose relatively conservative lines and watch for clues of instability.
• Give the new snow time to settle and stabilize before pushing into bigger terrain.

Friday night: Mostly clear, possible isolated flurries bringing up to 5 cm of new snow, moderate to strong wind from the southwest, alpine low temperature -5 C, freezing level 1200 m.

Saturday: 5-10 cm of snow in the morning with another 5-10 overnight, moderate to strong wind from the southwest, alpine high temperature -4 C, freezing level 1200 m dropping to valley bottom.

Sunday: A trace of snow, moderate wind from the southwest, alpine high temperature -4 C, freezing level rising to 1200 m before dropping to valley bottom overnight.

Monday: Up to 5 cm of snow, moderate wind from the southwest, alpine high temperature -4 C, freezing level valley bottom.

Soft storm slab avalanches and loose dry sluffing up to size 1.5, were produced by skier and explosive control work during the storm on Friday.

The previous storm yielded many large (size 2-3) storm slab avalanches both natural and explosive triggered, on Wednesday and Thursday.

We are sorry to report the news of 2 fatalities in the Montana Flathead region on Wednesday. The bed surface of the deadly avalanche was a crust formed and buried around Christmas. An illustrated photo can be found here. This crust has been observed widely in the Lizard Flathead region as well.

25-30 cm of recent low density snow sits over a dense slab. The new snow has likely been blown into wind slabs in the alpine by strong winds Friday night. 

Below 1700 m, two noteworthy crusts exist: a thin lens crust from a freezing rain event sits 50 cm below the surface, and below that, a thick, hard melt-freeze crust formed by warm temperatures around Christmastime, occasionally found with surface hoar crystals ontop. As these crusts become buried deeper, they have the potential to turn into a persistent slab problem. We'll be keeping an eye on them going forward. 

Hard snow in the mid snowpack sits above faceted snow and crusts near the bottom of the snowpack (100-170 cm deep). This weak lower snowpack has not been an active avalanche problem recently.