The Harrison 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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4.93 inches of rain fell in two days, the most for this week of the year since records began in 1898. The next wettest, 4.54 inches, fell in 1993.
Harrison’s center stands about 410 ft above sea level. Within three miles the land runs from 360 ft to 490 ft, a difference of 130 ft: gently rolling country. The highest named summit within 15 miles is Grassy Knob, about 780 ft, 14 miles south-southwest.
The section below crosses 5 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 50×. 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, sandstone. Age: Early Pennsylvanian to Middle Pennsylvanian, 307 to 324 million years old. About 11 mi of the line.
Shale, sandstone, coal. Age: Middle Pennsylvanian to Late Pennsylvanian, 304 to 315 million years old. About 7 mi of the line.
Shale, limestone. Age: Late Pennsylvanian, 304 to 307 million years old. About 3 mi of the line.
Limestone, sandstone, shale. Age: Late Mississippian, 324 to 331 million years old. About 2 mi of the line.
Shale, sandstone. Age: Early Pennsylvanian, 315 to 324 million years old. About 0.6 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 Harrison reaches the Gulf of America by way of the Big Muddy and the Mississippi: about 1,090 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Harrison; river miles along the main stem, rounded.
Harrison has a humid subtropical climate. Summer afternoons average 88° in July; winter nights fall to about 25° in January. About 44 inches of rain fall in a normal year.
On November 14 Harrison normally reaches 57° and falls to 35°. The record high is 78°, in 1978; the record low 10°, in 1986. The most rain on this date, 1.60 in, fell in 1993.
Normals 1991–2020 and records since 1898 from the Carbondale Area threaded record (Carbondale Southern Illinois Airport, 5 miles east-southeast). NOAA, through RCC-ACIS.
