As the storm hits, heavy snowfall and strong winds will rapidly load an already touchy snowpack. Avoid exposure to avalanche terrain. Travel in areas exposed to run-outs is not recommended; large avalanches are expected to run to valley bottom.
Weather Forecast
Another intense storm is beginning. 20-30cm of snow are expected by tomorrow morning, with freezing levels rising to 1700m. Winds will increase from light to strong as the storm progresses. Heavy precip will continue on Friday, with another 30cm of snow, freezing levels at 1800m, and sustained winds. Another 15cm is expected on Saturday.
Snowpack Summary
The Jan 30 surface hoar/crust layer, which exists up to 2200m, is down 30-50cm. Snowpack tests indicate that the storm slab may bond poorly to the crust, which acts as a smooth bed surface. Windloading will increase slab properties in lee areas. Jan 15 surface hoar layer is down 70-110cm and tests indicate it is still reactive in some areas.
Avalanche Summary
Light winds and flurries didn't add enough load to trigger many avalanches yesterday. There were a few natural avalanches to size 2 observed. Small slabs triggered by skiers indicated that the slab is forming. On Tuesday skiers accidentally triggered a size 2.5 avalanche from a SE aspect at 2120m. The avalanche propagated ~200m wide and ran ~600m.
Confidence
Timing, track, or intensity of incoming weather system is uncertain
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.