The Grass Valley 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.
Mostly sunny
Partly cloudy; warmer
Showers likely; cooler
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−8° on Nov. 12, 1985, the coldest reading for this week of the year since 1877. Next is −5° in 1955.
Grass Valley’s center stands about 4,420 ft above sea level. Within three miles the land runs from 4,320 ft to 5,160 ft, a difference of 840 ft: hilly country. The highest named summit within 15 miles is Sonoma Peak, about 9,310 ft, 9 miles east-northeast.
Under the town center the state geologic map shows Alluvium, undifferentiated (coarse-detrital, fine-detrital), from the Pleistocene to Holocene, less than 2.6 million years old.
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 4×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Age: Cambrian to Devonian, 359 to 497 million years old. About 4 mi of the line.
Coarse-detrital, fine-detrital. Age: Pleistocene to Holocene, less than 2.6 million years old. About 4 mi of the line.
Sandstone, shale, siltstone. Age: Late Devonian, 359 to 384 million years old. About 4 mi of the line.
Coarse-detrital, fine-detrital. Age: Pliocene to Pleistocene, less than 5.3 million years old. About 3 mi of the line.
Shale, siltstone, sandstone. Age: Late Triassic to Early Jurassic, 175 to 237 million years old. About 3 mi of the line.
Gravel, sand. Age: Pliocene to Pleistocene, less than 5.3 million years old. About 2 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 Grass Valley reaches the Great Basin by way of Clear Creek: about 11 river miles. The Great Basin has no outlet to the sea: the water leaves only by evaporating or soaking into the ground.
Often dry. About 100% of the way is mapped as streams that run only after rain or snowmelt; the water makes the whole trip in floods.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Grass Valley; river miles along the main stem, rounded.
Grass Valley has a cold semi-arid climate. Summer afternoons average 95° in July; winter nights fall to about 19° in December. A normal year brings about 22 inches of snow; with the rain, that comes to about 8 inches of water.
On November 14 Grass Valley normally reaches 55° and falls to 24°. The record high is 71°, in 2016; the record low −3°, in 1985. The most rain on this date, 0.38 in, fell in 1965.
Normals 1991–2020 and records since 1877 from the Winnemucca Area threaded record (Winnemucca Airport, 8 miles north-northwest, 120 ft lower). NOAA, through RCC-ACIS.
