The Topock 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.
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90° on Nov. 12, 1934, the hottest reading for this week of the year since 1888. Next is 89° in 1973.
Topock’s center stands about 490 ft above sea level. Within three miles the land runs from 450 ft to 1,570 ft, a difference of 1,120 ft: steep hill country. The highest named summit within 15 miles is Chemehuevi Peak, about 3,610 ft, 13 miles south-southwest.
Under the town center the state geologic map shows Quaternary surficial deposits, undivided (sand, silt, clay), from the Pleistocene to Holocene, less than 2 million years old.
The section below crosses 5 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 8×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sand, silt, clay. Age: Pleistocene to Holocene, less than 2 million years old. About 10 mi of the line.
Granite. Age: Paleoproterozoic to Early Miocene, 18 to 1,680 million years old. About 5 mi of the line.
Orthogneiss. Age: Paleoproterozoic to Miocene, 5.3 to 2,500 million years old. About 5 mi of the line.
Gravel, sand. Age: Late Pliocene to Pleistocene, 0.8 to 3 million years old. About 3 mi of the line.
Gneiss. Age: Paleoproterozoic to Miocene, 5.3 to 2,500 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.
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 Topock reaches the Gulf of California by way of Lost Lake and the Colorado: about 330 river miles.
Lakes on the way: Lake Havasu and Lost Lake.
Seldom reaches the sea. Dams and canals now take nearly all of the Colorado before its old delta in Mexico.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Topock; river miles along the main stem, rounded.
Topock has a hot desert climate. Summer afternoons average 111° in July; winter nights fall to about 45° in December. About 4 inches of rain fall in a normal year.
On November 14 Topock normally reaches 76° and falls to 53°. The record high is 88°, in 2021; the record low 34°, in 1916. The most rain on this date, 0.73 in, fell in 1910.
Normals 1991–2020 and records since 1888 from the Needles Area threaded record (Needles Airport, 9 miles west-northwest, 400 ft higher). NOAA, through RCC-ACIS.
