The Ohlman 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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4.54 inches of rain fell in two days, the most for this week of the year since records began in 1890. The next wettest, 2.92 inches, fell in 1978.
Ohlman’s center stands about 690 ft above sea level. Within three miles the land runs from 650 ft to 760 ft, a difference of 110 ft: gently rolling country.
Under the town center the state geologic map shows Mattoon Formation (shale), from the Late Pennsylvanian, 304 to 307 million years old.
The section below crosses 2 rock units mapped at the surface.
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. Age: Late Pennsylvanian, 304 to 307 million years old. About 13 mi of the line.
Shale, sandstone, limestone. Age: Late Pennsylvanian, 304 to 307 million years old. About 11 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 Ohlman reaches the Gulf of America by way of the South Fork Sangamon, the Sangamon, the Illinois and the Mississippi: about 1,450 river miles.
1,190 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Ohlman; river miles along the main stem, rounded.
Ohlman has a hot-summer humid continental climate. Summer afternoons average 87° in July; winter nights fall to about 19° in January. A normal year brings about 14 inches of snow; with the rain, that comes to about 42 inches of water.
On November 14 Ohlman normally reaches 54° and falls to 34°. The record high is 78°, in 1999; the record low 9°, in 1900. The most rain on this date, 2.74 in, fell in 1978.
Normals 1991–2020 and records since 1890 at Pana, 7 miles east-northeast. NOAA, through RCC-ACIS.
