Avalanche Forecast

After a dynamic period of natural and human-triggered avalanches earlier this week, reports of new avalanches have started to taper. However, with little change in the snowpack structure triggering large persistent slab avalanches remains a concern. Human-triggered avalanches are still likely in alpine and treeline terrain, especially in steep, shallow rocky areas. This notable avalanche continues to provide evidence that the layers described in the snowpack summary are with us for a while.

Roughly 40 cm of recent snow has settled into a slab that overlies weak faceted grains. The snow is also stressing buried weak layers, including:

• A surface hoar layer buried in mid-December that is 40 to 60 cm deep

• Weak faceted snow and decomposing crusts near the bottom of the snowpack, ranging from 70 to 150 cm deep.

These layers have produced large avalanches over the past week and need more time to strengthen.

Wednesday Night

Mainly cloudy overnight, no precipitation. 5 to 10 km/h southeast wind, treeline temperature -7 °C.

Thursday

Mostly cloudy, a trace of new snow, 5 to 10 km/h south wind, treeline temperature -6 °C.

Cloudy with sunny periods, possible flurries, 10 to 15 km/h southeast wind, treeline temperature -5 °C.

A mix of sun and clouds, increasing through the day, trace amounts of snow. 5 to 15 km/h south wind, treeline temperatures -5 °C.

More details can be found in the Mountain Weather Forecast.

• Choose conservative terrain and watch for clues of instability.
• Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
• Remote triggering is a concern, watch out for adjacent and overhead slopes.
• Back off if you encounter whumpfing, hollow sounds, or shooting cracks.