The next storm moves in Friday evening. Watch for changing conditions and pay attention to what is on the snow surface. Friday's snow surface could become Saturday's problem layer.
Given that recent winds have varied in direction, wind slabs may be found on multiple aspects. Winds are forecast to shift back to southwest and increase in strength on Friday. Pay attention to these changing conditions, as they may form fresh wind slabs that are reactive to human triggers.
Another powerful storm is expected to move in late Friday afternoon
Thursday night: Clearing overnight, no expected precipitation, moderate northwest winds becoming west and decreasing to light, low treeline temperatures near -5 C, freezing level dropping to 200 m.
Friday: Increasing cloudiness, light flurries possible in the late afternoon, winds becoming southwest and increasing to moderate, high treeline temperatures near -4 C, freezing level around 500 m.
Saturday: Overcast, 50-80 mm of precipitation, extreme southwest winds, treeline temperatures rising to near 0 C, freezing level rising to around 900 m in the north of the region and around 1500 m in the south.
Sunday: Cloudy, 5-15 mm of precipitation, southwest winds decreasing from moderate to light, high treeline temperatures near -2 C, freezing level around 700 m.
On Wednesday, operators reported several small (size 1) human-triggered avalanches on northerly aspects at treeline elevations. These avalanches released in the recent snow from ski cuts. It may be possible to human trigger similar avalanches in wind-drifted areas at upper elevations on Friday.
Snow quality has been at a premium this week (see this MIN report from the Mt Becher area on Tuesday), and the region picked up another 5-15 cm of light snow on Wednesday. Winds have varied in speed and direction with an ample supply of light, cold snow for transport. On Wednesday, observers reported active wind transport at ridgetops in this MIN report in the Mt Brooks area. This has likely created sensitive wind slabs on a wide range of aspects in wind-exposed areas.
Below 70-100 cm of snow from the past week, two crust layers can be found that formed in early December. Small facets (sugary snow) have been reported near these crusts that may transition into a persistent slab problem. Recent snowpack tests have demonstrated instability at this interface, though with limited propagation potential. This layer could have potential to be triggered in shallow, rocky zones near ridge tops, where the facets are more developed and where the crust layers are more accessible to the weight of a person or machine. Check out this MIN report from the Elk Mountain area on Tuesday.
Below these crust layers, the snowpack is generally well-settled. Early season hazards such as rocks, stumps, and open creeks remain at lower elevations.
