Another storm begins to move into northern California today (Wed) with moderate to strong South to Southwesterly winds and up to 5” to 10” of new snow possible by Thursday AM. Mammoth Mountain has seen steady moderate to strong Southwesterly winds overnight (Tues) and is forecasted to continue thru Wednesday night into Thursday AM. With the forecasted moderate to strong winds, downwind fetches still have enough transportable snow to produce another round of Wind Slabs in the mid to upper elevations on W-NW-N-NE-E-SE aspects today and bump the hazard from Moderate to Considerable by Thursday AM as new snow accumulates and begins to form additional Wind Slabs more broadly throughout mid and upper elevations. Watch for signs of blowing snow and wind loading (snow banners, recent cornice formation, and fresh drifts).
Treeline and below (especially in the Mammoth area) - due to the recent cold temperatures the persistent weak layer that has plagued the region through much of the early part of the season is showing signs of further weakening with possible failure in isolated locations from ~9,000’ to ~10,500’ , renewing concerns for potential deep releases if this trend continues. A recent report of whumphing in the Mammoth Lakes Basin and tests indicating propensity for propagation highlights this problem layer and the potential for failure. Currently, this layer is not widely reactive but it will need to be closely monitored as the snowpack adjusts to the new snowload from the approaching storm system. Currently the possibility remains LOW: Natural and triggered avalanches are unlikely but not impossible and the resulting avalanche could be large. Whumphs (sudden collapse) are a strong sign of instability. Do your own stability assessments, especially as you enter steeper or complex terrain.
There is an off chance that areas that receive the upper end of the forecasted snowfall (~10” +) may see an elevated concern for localized storm slabs, primarily in the mid elevations.
Below ~9,000’, natural and triggered releases are unlikely due to thin snow coverage (below threshold).