The Harrisburg 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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11° on Nov. 13, 2019, the coldest reading for this week of the year since 1878. Next is 12° in 1883.
Harrisburg’s center stands about 800 ft above sea level. Within three miles the land runs from 760 ft to 940 ft, a difference of 180 ft: gently rolling country.
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 54×. 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. Age: Silurian, 422 to 445 million years old. About 11 mi of the line.
Shale, black-shale. Age: Devonian, 359 to 422 million years old. About 5 mi of the line.
Limestone. Age: Devonian, 359 to 422 million years old. About 5 mi of the line.
Dolostone. Age: Silurian, 428 to 445 million years old. About 3 mi of the line.
Dolostone, limestone, shale. Age: Silurian, 422 to 445 million years old. About 0.8 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 Harrisburg reaches the Gulf of America by way of Springwater Run, Big Darby Creek, the Scioto, the Ohio and the Mississippi: about 1,710 river miles.
970 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Harrisburg; river miles along the main stem, rounded.
Harrisburg has a hot-summer humid continental climate. Summer afternoons average 85° in July; winter nights fall to about 22° in January. A normal year brings about 28 inches of snow; with the rain, that comes to about 42 inches of water.
On November 14 Harrisburg normally reaches 53° and falls to 35°. The record high is 74°, in 1909; the record low 12°, in 1986. The most rain on this date, 1.26 in, fell in 1897.
Normals 1991–2020 and records since 1878 from the Columbus Area threaded record (John Glenn International Airport, 20 miles northeast). NOAA, through RCC-ACIS.
