Very large avalanches will occur over the next few days.
Avoid all avalanche terrain!!!
Very large persistent slab avalanches are occurring regularly in treeline and alpine terrain. The intense warming over the next few days will make these even more likely. These avalanches could run into below treeline terrain.
Warming, and/or cornice falls, could trigger slabs in the recent storm snow.
Sudden warming will produce widespread wet loose avalanches, especially on steep sun-exposed slopes.
Large to very large (size 2 to 3) persistent slab avalanches are being reported across the region on a regular basis. Most have been naturally triggered, although some have been remote-triggered from 150 to 300 m away (most recently on Tuesday). There have also been reports of widespread whumpfing.
Natural storm slab avalanches (mostly size 1 to 2) were also observed during the stormy weather earlier this week.
Rapidly rising freezing levels on Thursday will melt surfaces on all terrain except for high north-facing slopes. 40 to 80 cm of snow from the past week is rapidly settling, but some storm slab instabilities may still be present, especially in wind-affected areas. Storm snow covers a variety of layers including surface hoar in isolated shady areas.
A weak layer composed of weak faceted grains on a crust is now buried 80 to 150 cm deep. This layer remains sensitive to both human and natural triggers and continues to produce large, destructive avalanches.
The snowpack below this layer is strong and bonded.
Wednesday Night
Mostly clear. 20 km/h northwest ridgetop wind. Treeline temperature -5 °C.
Thursday
Mostly sunny. 20 km/h northwest ridgetop wind. Treeline temperature +3 °C with freezing level climbing to 3000 m by midday.
Friday
Sunny. 15 km/h north wind. Treeline temperature +6 °C with freezing level climbing to 3300 m.
Saturday
Sunny. 25 km/h southeast ridgetop wind. Treeline temperature +8 °C with freezing level sustained at 3300 m.
More details can be found in the Mountain Weather Forecast.
