The Erwin 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.
Mostly sunny
Mostly sunny; warmer
Mostly sunny
Partly cloudy
Mostly cloudy
Partly cloudy; cooler
Showers likely
73° on Nov. 15, 1953, the hottest reading for this week of the year since 1893. Next is 72° in 2001.
Erwin’s center stands about 1,860 ft above sea level. Within three miles the land runs from 1,770 ft to 1,880 ft, a difference of 110 ft: gently rolling country.
Under the town center the state geologic map shows Pierre Shale (shale, bentonite), from the Late Cretaceous, 66 to 100 million years old.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 64×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Shale, bentonite. Age: Late Cretaceous, 66 to 100 million years old. About 24 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 Erwin reaches the Gulf of America by way of Lake Thompson, the East Fork Vermillion, the Vermillion, the Missouri and the Mississippi: about 2,150 river miles.
Lake on the way: Lake Thompson.
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 Erwin; river miles along the main stem, rounded.
Erwin has a warm-summer humid continental climate. Summer afternoons average 82° in July; winter nights fall to about 5° in January. A normal year brings about 41 inches of snow; with the rain, that comes to about 26 inches of water.
On November 14 Erwin normally reaches 41° and falls to 23°. The record high is 72°, in 1953; the record low −15°, in 1959. The most rain on this date, 0.63 in, fell in 1928.
Normals 1991–2020 and records since 1893 at De Smet, 9 miles southwest, 160 ft lower. NOAA, through RCC-ACIS.
