The New Underwood 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
Mostly sunny; warmer
Mostly sunny
Partly cloudy
Mostly sunny; cooler
Partly cloudy
Chance of showers
78° on Nov. 12, 1990, the hottest reading for this week of the year since 1942. Next is 78° in 1999.
New Underwood’s center stands about 2,880 ft above sea level. Within three miles the land runs from 2,800 ft to 3,050 ft, a difference of 250 ft: rolling country. The highest named summit within 15 miles is Thompson Butte, about 3,380 ft, 14 miles south-southwest.
Under the town center the state geologic map shows Pierre Shale (shale, bentonite), from the Late Cretaceous, 66 to 100 million years old.
The section below crosses 3 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 29×. 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 10 mi of the line.
Coarse-detrital, fine-detrital. Age: Quaternary, less than 2.6 million years old. About 10 mi of the line.
Shale, bentonite. Age: Late Cretaceous, 66 to 100 million years old. About 4 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 New Underwood reaches the Gulf of America by way of Boxelder Creek, the Cheyenne, the Missouri and the Mississippi: about 2,460 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 New Underwood; river miles along the main stem, rounded.
New Underwood has a dry-winter hot-summer continental climate. Summer afternoons average 86° in July; winter nights fall to about 13° in January. A normal year brings about 48 inches of snow; with the rain, that comes to about 17 inches of water.
On November 14 New Underwood normally reaches 48° and falls to 22°. The record high is 78°, in 1990; the record low −19°, in 1959. The most rain on this date, 0.52 in, fell in 1956.
Normals 1991–2020 and records since 1942 from the Rapid City Area threaded record (Rapid City Regional Airport, 11 miles west-southwest, 280 ft higher). NOAA, through RCC-ACIS.
