The Sea Ranch plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
Partly cloudy
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27° on Nov. 12, 1985, the coldest reading for this week of the year since 1895. Next is 29° in 1987.
Sea Ranch’s center stands about 110 ft above sea level. Within three miles the land runs from 10 ft to 1,080 ft, a difference of 1,070 ft: steep hill country. Open water lies within three miles. The highest named summit within 15 miles is Black Mountain, about 2,610 ft, 11 miles east-northeast.
Under the town center the state geologic map shows Quaternary alluvium and marine deposits (coarse-detrital), from the Pleistocene to Holocene, less than 2.6 million years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 9×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sandstone, mudstone. Age: Late Cretaceous to Pliocene, 2.6 to 100 million years old. About 8 mi of the line.
Mica-schist. Age: Early Cretaceous, 110 to 143 million years old. About 1 mi of the line.
Melange. Age: Jurassic to Cretaceous, 66 to 202 million years old. About 1 mi of the line.
Sandstone, siltstone-mudstone. Age: Late Cretaceous, 66 to 100 million years old. About 0.6 mi of the line.
Coarse-detrital. Age: Pleistocene to Holocene, less than 2.6 million years old. About 0.4 mi of the line.
Sandstone, mudstone. Age: Miocene to Pleistocene, less than 23 million years old. About 0.3 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale.
Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.
Rain that falls on Sea Ranch runs straight into the Pacific Ocean.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Sea Ranch; river miles along the main stem, rounded.
Sea Ranch has a warm-summer Mediterranean climate. Summer afternoons average 67° in August; winter nights fall to about 42° in January. About 39 inches of rain fall in a normal year.
On November 14 Sea Ranch normally reaches 61° and falls to 44°. The record high is 73°, in 1990; the record low 30°, in 1985. The most rain on this date, 2.10 in, fell in 1972.
Normals 1991–2020 and records since 1895 at Fort Ross, 18 miles southeast. NOAA, through RCC-ACIS.
