The Sinnamahoning 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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76° on Nov. 11, 2020, the hottest reading for this week of the year since 1969. Next is 72° in 1975.
Sinnamahoning’s center stands about 900 ft above sea level. Within three miles the land runs from 780 ft to 2,200 ft, a difference of 1,420 ft: steep hill country. The highest named summit within 15 miles is Old Round Top, about 2,360 ft, 15 miles west-southwest.
Under the town center the state geologic map shows Catskill Formation (sandstone, siltstone, shale), from the Late Devonian, 359 to 384 million years old.
The section below crosses 3 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 13×. 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, siltstone. Age: Devonian to Carboniferous, 324 to 422 million years old. About 9 mi of the line.
Sandstone, conglomerate. Age: Carboniferous, 299 to 324 million years old. About 9 mi of the line.
Sandstone, siltstone, shale. Age: Late Devonian, 359 to 384 million years old. About 6 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 Sinnamahoning reaches Chesapeake Bay and the Atlantic Ocean by way of Grove Run, Sinnemahoning Creek, the West Branch Susquehanna and the Susquehanna: about 250 river miles.
Lake on the way: Lake Aldred.
110 miles of the trip are on the West Branch Susquehanna.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Sinnamahoning; river miles along the main stem, rounded.
Sinnamahoning has a warm-summer humid continental climate. Summer afternoons average 81° in July; winter nights fall to about 16° in January. A normal year brings about 39 inches of snow; with the rain, that comes to about 43 inches of water.
On November 14 Sinnamahoning normally reaches 49° and falls to 29°. The record high is 67°, in 2009; the record low 13°, in 2019. The most rain on this date, 0.77 in, fell in 1997.
Normals 1991–2020 and records since 1969 at Stevenson Dam, 7 miles northeast. NOAA, through RCC-ACIS.
