The Addison 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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77° on Nov. 11, 2020, the hottest reading for this week of the year since 1946. Next is 75° in 1993.
Addison’s center stands about 2,050 ft above sea level. Within three miles the land runs from 1,430 ft to 2,720 ft, a difference of 1,290 ft: steep hill country. The highest named summit within 15 miles is Mount Davis, about 3,220 ft, 9 miles east-northeast.
Under the town center the state geologic map shows Casselman Formation (shale, clastic), from the Carboniferous, 299 to 324 million years old.
The section below crosses 9 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 11×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sandstone. Age: Carboniferous, 299 to 324 million years old. About 6 mi of the line.
Shale, clastic. Age: Carboniferous, 299 to 324 million years old. About 4 mi of the line.
Shale, siltstone, sandstone. Age: Carboniferous, 324 to 359 million years old. About 4 mi of the line.
Claystone, shale. Age: Carboniferous, 299 to 324 million years old. About 3 mi of the line.
Sandstone, siltstone, shale. Age: Carboniferous, 299 to 324 million years old. About 2 mi of the line.
Shale, siltstone, sandstone. Age: Carboniferous, 299 to 324 million years old. About 2 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 3 smaller units along the line are not listed.
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 Addison reaches the Gulf of America by way of Cucumber Run, the Casselman, the Youghiogheny, the Monongahela, the Ohio and the Mississippi: about 2,040 river miles.
970 miles of the trip are on the Ohio.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Addison; river miles along the main stem, rounded.
Addison has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 19° in January. A normal year brings about 61 inches of snow; with the rain, that comes to about 47 inches of water.
On November 14 Addison normally reaches 52° and falls to 30°. The record high is 74°, in 1989; the record low 7°, in 1986. The most rain on this date, 0.90 in, fell in 1972.
Normals 1991–2020 and records since 1946 at Confluence 1 SW Dam, 4 miles north-northwest, 560 ft lower. NOAA, through RCC-ACIS.
