The Carroll Valley 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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77° on Nov. 15, 1973, the hottest reading for this week of the year since 1956. Next is 76° in 2020.
Carroll Valley’s center stands about 740 ft above sea level. Within three miles the land runs from 460 ft to 1,480 ft, a difference of 1,020 ft: steep hill country. The highest named summit within 15 miles is Quirauk Mountain, about 2,150 ft, 8 miles west-southwest.
Under the town center the state geologic map shows Metabasalt, from the Precambrian.
The section below crosses 10 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.
Shale, sandstone. Age: Triassic, 202 to 252 million years old. About 6 mi of the line.
Quartzite. Age: Cambrian, 487 to 542 million years old. About 6 mi of the line.
Sandstone, shale. Age: Triassic, 202 to 252 million years old. About 3 mi of the line.
Age: Precambrian. About 3 mi of the line.
Age: Precambrian. About 3 mi of the line.
Dolostone. Age: Cambrian, 487 to 542 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. 4 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 Carroll Valley reaches Chesapeake Bay and the Atlantic Ocean by way of Toms Creek, the Monocacy and the Potomac: about 220 river miles.
160 miles of the trip are on the Potomac.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Carroll Valley; river miles along the main stem, rounded.
Carroll Valley has a hot-summer humid continental climate. Summer afternoons average 86° in July; winter nights fall to about 22° in January. A normal year brings about 28 inches of snow; with the rain, that comes to about 47 inches of water.
On November 14 Carroll Valley normally reaches 55° and falls to 34°. The record high is 72°, in 1989; the record low 15°, in 1986. The most rain on this date, 2.25 in, fell in 1972.
Normals 1991–2020 and records since 1956 at Emmitsburg 2 SE, 7 miles southeast, 340 ft lower. NOAA, through RCC-ACIS.
