The Gahanna 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.
Gahanna’s center stands about 800 ft above sea level. Within three miles the land runs from 780 ft to 1,000 ft, a difference of 220 ft: rolling country. The highest named summit within 15 miles is Beavers Hill, about 1,260 ft, 11 miles east-northeast.
Under the town center the state geologic map shows Ohio Shale (shale, black-shale), from the Devonian, 359 to 422 million years old.
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 35×. 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, black-shale. Age: Devonian, 359 to 422 million years old. About 11 mi of the line.
Sandstone, shale. Age: Devonian, 359 to 422 million years old. About 6 mi of the line.
Limestone. Age: Devonian, 359 to 422 million years old. About 4 mi of the line.
Shale, siltstone, sandstone. Age: Devonian to Carboniferous, 324 to 422 million years old. About 3 mi of the line.
Dolostone. 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 Gahanna reaches the Gulf of America by way of Big Walnut Creek, the Scioto, the Ohio and the Mississippi: about 1,740 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 Gahanna; river miles along the main stem, rounded.
Gahanna 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 Gahanna 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, here). NOAA, through RCC-ACIS.
