The San Carlos 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.
90° on Nov. 12, 1934, the hottest reading for this week of the year since 1900. Next is 89° in 1906.
San Carlos’s center stands about 2,640 ft above sea level. Within three miles the land runs from 2,580 ft to 3,460 ft, a difference of 880 ft: hilly country. The highest named summit within 15 miles is Hog Mountain, about 5,670 ft, 12 miles west-southwest.
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.
Conglomerate, sandstone. Age: Early Miocene to Pleistocene, 2 to 16 million years old. About 13 mi of the line.
Basalt. Age: Early Pliocene to Holocene, less than 4 million years old. About 4 mi of the line.
Sand, silt, clay. Age: Pleistocene to Holocene, less than 2 million years old. About 3 mi of the line.
Basalt, andesite, dacite. Age: Middle Eocene to Late Miocene, 11 to 38 million years old. About 2 mi of the line.
Basalt. Age: Early Miocene to Late Miocene, 8 to 16 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 San Carlos reaches the Gulf of California by way of Gilson Wash, the San Carlos, the Gila and the Colorado: about 510 river miles.
370 miles of the trip are on the Gila.
Often dry. About 50% of the way is mapped as streams that run only after rain or snowmelt; the water makes the whole trip in floods.
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 San Carlos; river miles along the main stem, rounded.
San Carlos has a hot semi-arid climate. Summer afternoons average 99° in July; winter nights fall to about 31° in January. About 13 inches of rain fall in a normal year.
On November 14 San Carlos normally reaches 69° and falls to 39°. The record high is 89°, in 1906; the record low 22°, in 1938. The most rain on this date, 1.07 in, fell in 1968.
Normals 1991–2020 and records since 1900 at San Carlos Reservoir, 12 miles south-southwest, 110 ft lower. NOAA, through RCC-ACIS.