People could trigger wind slab avalanches today, especially in exposed terrain at upper elevations and on drifted mid-elevation slopes facing the northwest through southeast. Wind slab avalanches up to 3 feet thick might fail on a preexisting layer of weak surface snow.

• Avoid travel on and under steep slopes with thick and/or stiff deposits of recently wind-drifted snow.
• Cracking is an obvious sign of instability.
• Soft wind slabs of drifted new snow might be quite sensitive to human triggering, while hard, older wind slabs can be devious, sometimes allowing people to get well out on them before releasing suddenly, like a mousetrap.

Read my Blog about Wind, Drifting, and Avalanches

There is lingering potential on some isolated slopes with poor snow structure for large and destructive hard slab avalanches that fail on a buried persistent weak layer near the ground.

• We are still concerned by a buried persistent weak layer problem that likely still exists in outlying upper-elevation terrain, especially on northerly facing slopes in the southern half of the zone. A weak layer of moist faceted November snow lurks near the ground. Destructive, hard slab avalanches up to 4 feet deep remain possible in isolated drifted terrain.
• Another potential buried persistent weak layer consisting of glittery surface hoar and/or small sugary grains of faceted snow may exist on last year's snow surface. Buried by the New Year's storm, it could have been preserved intact on some slopes. Slab avalanches today, up to three feet thick, could fail on a persistent weak layer in the Christmas-New Year's interface.

The danger of soft slab and loose avalanches of storm snow will increase as new snow rapidly stacks up on steep slopes this afternoon and overnight.

• Natural loose and soft slab avalanches of storm snow are increasingly possible, especially likely during periods of very heavy snowfall.
• People should stay off and out from under steep slopes as new snow rapidly accumulates and is drifted onto them.