The Colebrook 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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70° on Nov. 11, 2020, the hottest reading for this week of the year since 1884. Next is 67° in 1993.
Colebrook’s center stands about 1,180 ft above sea level. Within three miles the land runs from 640 ft to 1,490 ft, a difference of 850 ft: hilly country. The highest named summit within 15 miles is Bradford Mountain, about 1,970 ft, 10 miles west.
Under the town center the state geologic map shows Layered gneiss, from the Mesoproterozoic, 1 to 1.6 billion years old.
The section below crosses 12 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.
Gneiss. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 4 mi of the line.
Schist, gneiss. Age: Cambrian, 487 to 542 million years old. About 3 mi of the line.
Gneiss. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 3 mi of the line.
Schist, gneiss. Age: Cambrian, 487 to 542 million years old. About 3 mi of the line.
Schist, granofels. Age: Middle Ordovician, 459 to 471 million years old. About 3 mi of the line.
Schist. Age: Silurian to Devonian, 359 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. 6 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 Colebrook reaches Long Island Sound and the Atlantic Ocean by way of the West Branch Farmington, the Farmington and the Connecticut: about 120 river miles.
55 miles of the trip are on the Connecticut.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Colebrook; river miles along the main stem, rounded.
Colebrook has a warm-summer humid continental climate. Summer afternoons average 78° in July; winter nights fall to about 14° in January. A normal year brings about 75 inches of snow; with the rain, that comes to about 53 inches of water.
On November 14 Colebrook normally reaches 46° and falls to 31°. The record high is 64°, in 1964; the record low 10°, in 2019. The most rain on this date, 0.92 in, fell in 1988.
Normals 1991–2020 and records since 1884 at Norfolk 2 SW, 7 miles west, 160 ft higher. NOAA, through RCC-ACIS.
