Dry and dusty conditions have mostly prevailed this month due to a high pressure ridge that has remained parked off the California coast and deflecting storms systems well to the north of the forecast region. Finally, the pattern appears to be changing with the ridge beginning to flatten and signs of eastward progression. The combination of an extended dry spell, shallow snowpack, and cool nightly temperatures has produced strong faceting of the upper snowpack, especially northerly aspects, producing sugary weak snow throughout the upper snowpack.
The last storm to move through the region was a weak system on 12/21. The storm deposited ~ 1” to 4” of snow, primarily from Mammoth to Virginia Lakes and was accompanied by moderate to strong winds, depositing dense Wind Slabs on top of weak faceted snow. Normally, Wind Slabs tend to bond to the underlying snow within a few hours to ~couple of days. However, the widespread weak faceted (sugar) snow in the upper snowpack, especially on northerly facing aspects, has slowed the normal bonding and strengthening processes and maintains the potential for small isolated Wind Slabs to persist.
The snowpack in the Sierras remains thin and mostly confined to elevations above ~9,000 around Mammoth, possibly higher elsewhere. The snowpack near and above treeline alternates between soft facts in sheltered areas, wind stripped, wind deposited areas, and melt / freeze patches. The recent mid-day warming has produced a Melt/Freeze crust of varying supportiveness on solar aspects. Good skiing can be found on sheltered Northerly aspects or on Southerly aspects with enough coverage that are reportedly offering good spring-like skiing in the limited areas. Below treeline, the snowpack continues to be exceptionally thin. Early season conditions exist with numerous obstacles and many hazards just under the snow surface. As the winter progresses, the facets in the upper snowpack may form a weak layer, once buried.
