The South Annville 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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75° on Nov. 15, 1993, the hottest reading for this week of the year since 1948. Next is 74° in 1973.
South Annville’s center stands about 510 ft above sea level. Within three miles the land runs from 410 ft to 890 ft, a difference of 480 ft: hilly country. The highest named summit within 15 miles is Governor Dick Hill, about 1,190 ft, 4 miles southeast.
Under the town center the state geologic map shows Millbach and Schaefferstown Formations, undivided (limestone, dolostone), from the Cambrian, 487 to 542 million years old.
The section below crosses 16 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 21×. 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: Ordovician, 445 to 487 million years old. About 6 mi of the line.
Shale, siltstone. Age: Ordovician, 445 to 487 million years old. About 3 mi of the line.
Sandstone. Age: Triassic, 202 to 252 million years old. About 3 mi of the line.
Limestone, dolostone. Age: Ordovician, 445 to 487 million years old. About 2 mi of the line.
Limestone, dolostone. Age: Cambrian, 487 to 542 million years old. About 2 mi of the line.
Shale. Age: Ordovician, 445 to 487 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. 10 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 South Annville reaches Chesapeake Bay and the Atlantic Ocean by way of Gingrich Run, Killinger Creek, Quittapahilla Creek, Swatara Creek and the Susquehanna: about 95 river miles.
Lake on the way: Lake Aldred.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of South Annville; river miles along the main stem, rounded.
South Annville has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 22° in January. A normal year brings about 24 inches of snow; with the rain, that comes to about 46 inches of water.
On November 14 South Annville normally reaches 53° and falls to 34°. The record high is 72°, in 1989; the record low 17°, in 1986. The most rain on this date, 1.69 in, fell in 1972.
Normals 1991–2020 and records since 1948 at Lebanon 2 W, 4 miles northeast. NOAA, through RCC-ACIS.
