The East Rockhill 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.
Partly cloudy
Partly cloudy; warmer
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75° on Nov. 11, 2020, the hottest reading for this week of the year since 1948. Next is 72° in 2005.
East Rockhill’s center stands about 740 ft above sea level. Within three miles the land runs from 320 ft to 760 ft, a difference of 440 ft: hilly country. The highest named summit within 15 miles is Flint Hill, about 1,030 ft, 9 miles north-northwest.
Under the town center the state geologic map shows Diabase (basalt), from the Jurassic, 145 to 202 million years old.
The section below crosses 7 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 29×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Mudstone. Age: Triassic, 202 to 252 million years old. About 11 mi of the line.
Argillite. Age: Triassic, 202 to 252 million years old. About 6 mi of the line.
Basalt. Age: Jurassic, 145 to 202 million years old. About 4 mi of the line.
Conglomerate. Age: Triassic, 202 to 252 million years old. About 2 mi of the line.
Limestone, dolostone. Age: Ordovician, 445 to 487 million years old. About 0.9 mi of the line.
Gneiss. Age: Precambrian. About 0.5 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 1 smaller unit 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 East Rockhill reaches Delaware Bay and the Atlantic Ocean by way of Threemile Run, Tohickon Creek and the Delaware: about 140 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of East Rockhill; river miles along the main stem, rounded.
East Rockhill has a hot-summer humid continental climate. Summer afternoons average 85° in July; winter nights fall to about 19° in January. A normal year brings about 22 inches of snow; with the rain, that comes to about 52 inches of water.
On November 14 East Rockhill normally reaches 54° and falls to 32°. The record high is 66°, in 2010; the record low 18°, in 1996. The most rain on this date, 0.55 in, fell in 2008.
Normals 1991–2020 and records since 1948 at Sellersville, 4 miles south-southwest, 440 ft lower. NOAA, through RCC-ACIS.
