The Upper Mahanoy 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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74° on Nov. 11, 2020, the hottest reading for this week of the year since 1926. Next is 72° in 1973.
Upper Mahanoy’s center stands about 830 ft above sea level. Within three miles the land runs from 610 ft to 1,510 ft, a difference of 900 ft: hilly country. The highest named summit within 15 miles is Big Mountain, about 1,830 ft, 14 miles east-northeast.
Under the town center the state geologic map shows Irish Valley Member of Catskill Formation (siltstone), from the Late Devonian, 359 to 384 million years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 15×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Siltstone. Age: Late Devonian, 359 to 384 million years old. About 14 mi of the line.
Siltstone, shale. Age: Late Devonian, 359 to 384 million years old. About 3 mi of the line.
Siltstone, mudstone. Age: Late Devonian, 359 to 384 million years old. About 2 mi of the line.
Shale, siltstone, sandstone. Age: Carboniferous, 324 to 359 million years old. About 2 mi of the line.
Sandstone, siltstone. Age: Late Devonian, 359 to 384 million years old. About 1 mi of the line.
Sandstone. Age: Carboniferous, 324 to 359 million years old. About 1 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 Upper Mahanoy reaches Chesapeake Bay and the Atlantic Ocean by way of Schwaben Creek, Mahanoy Creek and the Susquehanna: about 130 river miles.
Lake on the way: Lake Aldred.
75 miles of the trip are on the Susquehanna.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Upper Mahanoy; river miles along the main stem, rounded.
Upper Mahanoy 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 29 inches of snow; with the rain, that comes to about 44 inches of water.
On November 14 Upper Mahanoy normally reaches 51° and falls to 32°. The record high is 70°, in 1964; the record low 18°, in 2019. The most rain on this date, 0.97 in, fell in 1972.
Normals 1991–2020 and records since 1926 at Sunbury, 13 miles northwest, 260 ft lower. NOAA, through RCC-ACIS.
