The Larkfield-Wikiup 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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Mostly sunny
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3.48 inches of rain fell in two days, the most for this week of the year since records began in 1902. The next wettest, 3.20 inches, fell in 1920.
Larkfield-Wikiup’s center stands about 210 ft above sea level. Within three miles the land runs from 100 ft to 1,070 ft, a difference of 970 ft: steep hill country. The highest named summit within 15 miles is Mount Saint Helena, about 4,310 ft, 13 miles north-northeast.
The section below crosses 9 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.
Dacite. Age: Late Miocene to Late Pliocene, 3 to 7 million years old. About 8 mi of the line.
Coarse-detrital. Age: Pleistocene to Holocene, less than 2.6 million years old. About 5 mi of the line.
Coarse-detrital. Age: Pleistocene, less than 2.6 million years old. About 3 mi of the line.
Melange. Age: Jurassic to Cretaceous, 66 to 202 million years old. About 2 mi of the line.
Sandstone, conglomerate. Age: Miocene to Pleistocene, less than 23 million years old. About 2 mi of the line.
Sandstone, mudstone. Age: Miocene to Pleistocene, less than 23 million years old. About 1 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 3 smaller units along the line are not listed.
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.
A raindrop that lands in Larkfield-Wikiup reaches the Pacific Ocean by way of Mark West Creek and the Russian: about 35 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Larkfield-Wikiup; river miles along the main stem, rounded.
Larkfield-Wikiup has a warm-summer Mediterranean climate. Summer afternoons average 84° in September; winter nights fall to about 38° in January. About 32 inches of rain fall in a normal year.
On November 14 Larkfield-Wikiup normally reaches 68° and falls to 42°. The record high is 88°, in 2008; the record low 22°, in 1916. The most rain on this date, 2.27 in, fell in 1953.
Normals 1991–2020 and records since 1902 at Santa Rosa, 5 miles south-southeast. NOAA, through RCC-ACIS.
