The Rapid 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.
Partly cloudy
Sunny; warmer
Mostly sunny
Partly cloudy
Mostly sunny; cooler
Partly cloudy
Chance of showers
−15° on Nov. 14, 1959, the coldest reading for this week of the year since 1888. Next is −13° in 1916.
Rapid Valley’s center stands about 3,160 ft above sea level. Within three miles the land runs from 3,030 ft to 3,390 ft, a difference of 360 ft: rolling country. The highest named summit within 15 miles is Boulder Hill, about 5,250 ft, 14 miles west-southwest.
The section below crosses 12 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 14×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Coarse-detrital, clay. Age: Quaternary, less than 2.6 million years old. About 7 mi of the line.
Shale, bentonite. Age: Late Cretaceous, 66 to 100 million years old. About 5 mi of the line.
Coarse-detrital, fine-detrital. Age: Quaternary, less than 2.6 million years old. About 3 mi of the line.
Sandstone, siltstone, shale. Age: Late Pennsylvanian to Permian, 273 to 307 million years old. About 2 mi of the line.
Conglomerate. Age: Tertiary, 2.6 to 66 million years old. About 2 mi of the line.
Shale, mudstone, marlstone. Age: Late Cretaceous, 66 to 100 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. 6 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 Rapid Valley reaches the Gulf of America by way of Rapid Creek, the Cheyenne, the Missouri and the Mississippi: about 2,510 river miles.
Lakes on the way: Lake Oahe, Lake Sharpe, Lake Francis Case and Lewis and Clark Lake.
1,170 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Rapid Valley; river miles along the main stem, rounded.
Rapid Valley has a dry-winter hot-summer continental climate. Summer afternoons average 84° in July; winter nights fall to about 16° in January. A normal year brings about 54 inches of snow; with the rain, that comes to about 20 inches of water.
On November 14 Rapid Valley normally reaches 48° and falls to 27°. The record high is 79°, in 1894; the record low −15°, in 1959. The most rain on this date, 0.67 in, fell in 1956.
Normals 1991–2020 and records since 1888 from the Rapid City Downtown Area threaded record (Rapid City Wfo, 3 miles west-northwest, 220 ft higher). NOAA, through RCC-ACIS.
