The West Mountain 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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10° on Nov. 16, 1996, the coldest reading for this week of the year since 1937. Next is 14° in 1956.
West Mountain’s center stands about 820 ft above sea level. Within three miles the land runs from 420 ft to 970 ft, a difference of 550 ft: hilly country. The highest named summit within 15 miles is Mount Nimham, about 1,280 ft, 15 miles northwest.
Under the town center the state geologic map shows Gneiss of Highlands massifs (including Fordham Gneiss), from the Mesoproterozoic, 1 to 1.6 billion years old.
The section below crosses 15 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 22×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Biotite-gneiss. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 4 mi of the line.
Gneiss. Age: Early Devonian to Middle Devonian, 393 to 419 million years old. About 4 mi of the line.
Gneiss. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 2 mi of the line.
Gneiss. Age: Middle Ordovician, 459 to 471 million years old. About 2 mi of the line.
Gneiss. Age: Precambrian to Mesoproterozoic. About 2 mi of the line.
Schist, gneiss. Age: Early Ordovician to Middle Ordovician, 459 to 487 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. 9 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 West Mountain reaches New York Harbor and the Atlantic Ocean by way of the Waccabuc, the Cross, the Croton and the Hudson: about 65 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of West Mountain; river miles along the main stem, rounded.
West Mountain has a hot-summer humid continental climate. Summer afternoons average 85° in July; winter nights fall to about 21° in January. A normal year brings about 49 inches of snow; with the rain, that comes to about 53 inches of water.
On November 14 West Mountain normally reaches 51° and falls to 34°. The record high is 73°, in 1993; the record low 16°, in 1939. The most rain on this date, 2.42 in, fell in 1937.
Normals 1991–2020 and records since 1937 at Danbury, 9 miles northeast, 420 ft lower. NOAA, through RCC-ACIS.
