Moderate to strong southwest wind will redistribute loose and new snow and continue to form fresh wind slabs. Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
Moderate to strong southwest wind will continue to redistribute the recent snow. Expect to find more reactive deposits around ridge features. Be especially mindful around steep and convex openings in the trees. The new and recent snow may overlie a weak interface which could result in deeper and touchier than expected slabs.
A persistent slab problem formed by a crust down 100-270 cm has created a low likelihood, high consequence scenario that is difficult to forecast. Avoid likely trigger spots such as steep, rocky slopes with a shallow or thin to thick snowpack.
The same feature or path can slide repeatedly when the persistent weak layer gets reloaded by new snow.
Monday night: Increasing cloud coverage, trace of new snow, moderate southwest wind, treeline low around -5 °C, freezing level below valley bottom.
Tuesday: Cloudy, 5-10 cm new snow, moderate to strong southwest wind, treeline high around -1 °C, freezing level rising to 1300 m.
Wednesday: Cloudy, 10-20 cm new snow and rain at lower elevations, moderate southwest wind, treeline high around +2 °C, freezing level rising to 1900 m.
Thursday: Mostly sunny, up to 5 cm new snow, light to moderate southwest wind, treeline high around +4 °C, freezing level rising to 2300 m.
On Sunday, a few natural cornice failures resulting in size 2.5 avalanches were observed as well as a natural size 2 slab avalanche.
On Saturday, storm slab avalanches up to size 2.5 were triggered by explosives. Overnight, a large (size 3.5) natural storm slab avalanche released and a large (size 2.5) cornice failure occurred.
On Friday, storm slab avalanches released naturally up to size 2.5. Explosives triggered storm slabs to size 2.5, and skiers triggered avalanches to size 2. A large (size 2) natural cornice failure was reported likely having failed in the overnight storm.
The persistent slab problem has produced sporadic and spotty activity in the Lizard-Flathead and nearby regions.
The recent storm snow totals 40-50 cm. In open terrain and upper elevations, wind developed more reactive deposits around lee and convex features. This recent snow covered a hard, faceted snow surface which formed during cold temperatures and may take a little time to bond.
The most notable layer of concern in the snowpack is a crust that was formed in early December and is now down 100-270 cm. Activity on this layer has been sporadic, the most recent persistent slab avalanche in the region was reported on January 2. This layer has created a low likelihood, high consequence scenario which is best managed through conservative terrain choices and disciplined backcountry travel techniques.
