The Clappertown 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. 14, 1986, the coldest reading for this week of the year since 1948. Next is 12° in 1959.
Clappertown’s center stands about 1,150 ft above sea level. Within three miles the land runs from 910 ft to 1,960 ft, a difference of 1,050 ft: steep hill country. The highest named summit within 15 miles is Ritchey Knob, about 2,880 ft, 13 miles west-southwest.
Under the town center the state geologic map shows Bellefonte and Axemann Formations, undivided (dolostone, limestone), from the Ordovician, 445 to 487 million years old.
The section below crosses 19 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, shale. Age: Ordovician, 445 to 487 million years old. About 3 mi of the line.
Siltstone, shale. Age: Late Devonian, 359 to 384 million years old. About 2 mi of the line.
Black-shale. Age: Early Devonian to Middle Devonian, 384 to 422 million years old. About 2 mi of the line.
Dolostone. Age: Cambrian, 487 to 542 million years old. About 2 mi of the line.
Shale, sandstone. Age: Silurian, 422 to 445 million years old. About 2 mi of the line.
Quartzite. Age: Silurian, 422 to 445 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. 13 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 Clappertown reaches Chesapeake Bay and the Atlantic Ocean by way of Piney Creek, the Frankstown Branch Juniata, the Juniata and the Susquehanna: about 220 river miles.
Lake on the way: Lake Aldred.
100 miles of the trip are on the Juniata.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Clappertown; river miles along the main stem, rounded.
Clappertown has a hot-summer humid continental climate. Summer afternoons average 83° in July; winter nights fall to about 21° in January. About 37 inches of rain fall in a normal year.
On November 14 Clappertown normally reaches 51° and falls to 34°. The record high is 73°, in 1993; the record low 11°, in 1986. The most rain on this date, 2.25 in, fell in 1972.
Normals 1991–2020 and records since 1948 at Altoona Blair County Airport, 7 miles south-southwest, 320 ft higher. NOAA, through RCC-ACIS.
