The Mount Carroll 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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−2° on Nov. 12, 2019, the coldest reading for this week of the year since 1895. Next is −1° in 1898.
Mount Carroll’s center stands about 810 ft above sea level. Within three miles the land runs from 710 ft to 870 ft, a difference of 160 ft: gently rolling country.
Under the town center the state geologic map shows Galena Group (Trenton Limestone) (dolostone, limestone), from the Late Ordovician, 447 to 459 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 49×. 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, limestone. Age: Late Ordovician, 447 to 459 million years old. About 10 mi of the line.
Dolostone, limestone. Age: Silurian, 422 to 445 million years old. About 9 mi of the line.
Shale, limestone. Age: Late Ordovician, 445 to 454 million years old. About 5 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 Mount Carroll reaches the Gulf of America by way of Carroll Creek, the Plum and the Mississippi: about 1,540 river miles.
Lake on the way: Spring Lake.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Mount Carroll; river miles along the main stem, rounded.
Mount Carroll has a hot-summer humid continental climate. Summer afternoons average 85° in July; winter nights fall to about 11° in January. A normal year brings about 33 inches of snow; with the rain, that comes to about 40 inches of water.
On November 14 Mount Carroll normally reaches 49° and falls to 28°. The record high is 73°, in 1999; the record low 3°, in 1986. The most rain on this date, 1.30 in, fell in 1899.
Normals 1991–2020 and records since 1895 at Mount Carroll, here, 100 ft lower. NOAA, through RCC-ACIS.
