Northern California is a textbook example of Basin and Range topography, which I remembered from my geology studies with the Open University. A series of linear north-south mountain ranges, sloping down to foothills and flat valley bottoms. It’s characteristic of extensional tectonics, with fault-slip bounded basins. Somewhere, way underneath the floor, there’s heat, and in places in places magma, which surprises us with hot springs and steam vents. In the ranges the crustal blocks have rotated, one edge dipped, the other lifted. In this region the bounding foreland is the chain of the Sierra Nevada granite mountains.
Thick alluvium fills the valley floors, perfect for agriculture. Here in Sonoma it’s mostly vineyards. Field after field is marshalled into tows of T-shaped vines, single-trunked and double-branched, wired together for support. In early March, it’s too early for the leaves and the flower- and fruit-bearing side shoots. The vines are underplanted with mustard and another golden yellow flower I can’t identify from this distance. The recent weather has been so bad that many of the field edges are flooded. On a larger scale, the low ground between Vallejo and Sacramento is sodden and waterlogged. Fine weather for ducks, as the saying goes, and there are large numbers of them in the roadside ponds and channels.
The Russian River is bank-full and close to overtopping. It is fast-flowing, muddy, opaque. It hasn’t got much further to go though. From here it tips its sediment load into the mighty Pacific near Jenner-By-the-Sea. It will discolour the ocean quite far out this year, thanks to the atmospheric rivers of rain which have deluged the State of California for weeks now.
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