The Jefferson 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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16° on Nov. 16, 1996, the coldest reading for this week of the year since 1993. Next is 18° in 2017.
Jefferson’s center stands about 580 ft above sea level. Within three miles the land runs from 310 ft to 880 ft, a difference of 570 ft: hilly country. The highest named summit within 15 miles is Black Rock, about 1,870 ft, 15 miles north-northwest.
The section below crosses 11 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 16×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Metabasalt. Age: Proterozoic to Mesoproterozoic, 1 to 2.5 billion years old. About 7 mi of the line.
Gneiss. Age: Precambrian. About 6 mi of the line.
Sandstone, shale. Age: Triassic, 202 to 252 million years old. About 4 mi of the line.
Limestone. Age: Cambrian, 487 to 542 million years old. About 2 mi of the line.
Quartzite. Age: Cambrian, 487 to 542 million years old. About 2 mi of the line.
Quartzite. Age: Proterozoic to Cambrian, 487 to 2,500 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. 5 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 Jefferson reaches Chesapeake Bay and the Atlantic Ocean by way of Catoctin Creek and the Potomac: about 170 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Jefferson; river miles along the main stem, rounded.
Jefferson has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 25° in January. A normal year brings about 31 inches of snow; with the rain, that comes to about 48 inches of water.
On November 14 Jefferson normally reaches 54° and falls to 37°. The record high is 74°, in 1993; the record low 22°, in 2019. The most rain on this date, 1.90 in, fell in 1995.
Normals 1991–2020 and records since 1993 at Damascus 3 SSW, 17 miles east-southeast, 120 ft higher. NOAA, through RCC-ACIS.
