The Los Alamos 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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25° on Nov. 17, 1958, the coldest reading for this week of the year since 1906. Next is 26° in 1938.
Los Alamos’s center stands about 580 ft above sea level. Within three miles the land runs from 500 ft to 1,520 ft, a difference of 1,020 ft: steep hill country. The highest named summit within 15 miles is Zaca Peak, about 4,270 ft, 14 miles east.
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 5 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 7×. 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: Oligocene to Pliocene, 2.6 to 34 million years old. About 9 mi of the line.
Sandstone, mudstone. Age: Miocene to Pleistocene, less than 23 million years old. About 6 mi of the line.
Sandstone, conglomerate. Age: Miocene to Pleistocene, less than 23 million years old. About 5 mi of the line.
Coarse-detrital. Age: Pleistocene, less than 2.6 million years old. About 4 mi of the line.
Coarse-detrital. Age: Pleistocene to Holocene, less than 2.6 million years old. About 1.0 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 Los Alamos reaches the Pacific Ocean by way of San Antonio Creek: about 20 river miles.
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.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Los Alamos; river miles along the main stem, rounded.
Los Alamos has a warm-summer Mediterranean climate. Summer afternoons average 75° in September; winter nights fall to about 40° in December. About 13 inches of rain fall in a normal year.
On November 14 Los Alamos normally reaches 70° and falls to 45°. The record high is 91°, in 2008; the record low 30°, in 1985. The most rain on this date, 1.66 in, fell in 1953.
Normals 1991–2020 and records since 1906 from the Santa Maria Area threaded record (Santa Maria Public Airport, 15 miles northwest, 340 ft lower). NOAA, through RCC-ACIS.
