The Spring Grove 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.
71° on Nov. 14, 1999, the hottest reading for this week of the year since 1892. Next is 69° in 1917.
Spring Grove’s center stands about 1,330 ft above sea level. Within three miles the land runs from 1,040 ft to 1,320 ft, a difference of 280 ft: rolling country.
Under the town center the state geologic map shows Upper Ordovician (limestone, dolostone), from the Late Ordovician, 445 to 459 million years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 31×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Dolostone, sandstone. Age: Early Ordovician, 471 to 487 million years old. About 9 mi of the line.
Dolostone, sandstone. Age: Early Ordovician to Late Ordovician, 454 to 487 million years old. About 8 mi of the line.
Sandstone, siltstone, shale. Age: Cambrian, 487 to 497 million years old. About 3 mi of the line.
Shale, limestone, sandstone. Age: Middle Ordovician to Late Ordovician, 445 to 471 million years old. About 2 mi of the line.
Limestone, dolostone. Age: Late Ordovician, 445 to 459 million years old. About 2 mi of the line.
Sandstone, siltstone, shale. Age: Middle Cambrian to Cambrian, 487 to 521 million years old. About 0.4 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 Spring Grove reaches the Gulf of America by way of North Bear Creek, Bear Creek, the Upper Iowa and the Mississippi: about 1,690 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Spring Grove; river miles along the main stem, rounded.
Spring Grove has a warm-summer humid continental climate. Summer afternoons average 81° in July; winter nights fall to about 8° in January. A normal year brings about 45 inches of snow; with the rain, that comes to about 38 inches of water.
On November 14 Spring Grove normally reaches 43° and falls to 27°. The record high is 71°, in 1999; the record low −3°, in 1986. The most rain on this date, 1.40 in, fell in 1902.
Normals 1991–2020 and records since 1892 at Caledonia, 8 miles northeast, 200 ft lower. NOAA, through RCC-ACIS.