The Kirwin 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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Mostly sunny; warmer
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Showers likely; warmer
83° on Nov. 17, 2016, the hottest reading for this week of the year since 1952. Next is 80° in 1980.
Kirwin’s center stands about 1,700 ft above sea level. Within three miles the land runs from 1,660 ft to 1,830 ft, a difference of 170 ft: gently rolling country. The highest named summit within 15 miles is Blue Mound, about 2,060 ft, 12 miles north.
Under the town center the state geologic map shows Alluvium (sand, silt, clay), from the Pleistocene to Holocene, less than 2.6 million years old.
The section below crosses 4 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 51×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Silt. Age: Pleistocene to Holocene, less than 2.6 million years old. About 8 mi of the line.
Shale, limestone. Age: Late Cretaceous, 66 to 100 million years old. About 7 mi of the line.
Sand, silt, clay. Age: Pleistocene to Holocene, less than 2.6 million years old. About 4 mi of the line.
Arkose. Age: Miocene, 5.3 to 23 million years old. About 0.9 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 Kirwin reaches the Gulf of America by way of the North Fork Solomon, the Solomon, the Smoky Hill, the Kansas, the Missouri and the Mississippi: about 2,000 river miles.
Lake on the way: Waconda 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 Kirwin; river miles along the main stem, rounded.
Kirwin has a hot-summer humid continental climate. Summer afternoons average 92° in July; winter nights fall to about 13° in January. About 26 inches of rain fall in a normal year.
On November 14 Kirwin normally reaches 55° and falls to 25°. The record high is 78°, in 2025; the record low 1°, in 1959. The most rain on this date, 0.22 in, fell in 2002.
Normals 1991–2020 and records since 1952 at Kirwin Dam, here. NOAA, through RCC-ACIS.
