The Topsham 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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Partly cloudy; warmer
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71° on Nov. 11, 2020, the hottest reading for this week of the year since 1993. Next is 70° in 2022.
Topsham’s center stands about 150 ft above sea level. Within three miles the land runs from 10 ft to 280 ft, a difference of 270 ft: rolling country. The highest named summit within 15 miles is Hodgman Hill, about 660 ft, 15 miles north-northwest.
Under the town center the state geologic map shows Ordovician - Precambrian Z Cushing Formation (felsic-volcanic, mafic-volcanic), from the Neoproterozoic to Ordovician, 445 to 1,000 million years old.
The section below crosses 4 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 43×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Felsic-volcanic, mafic-volcanic. Age: Neoproterozoic to Ordovician, 445 to 1,000 million years old. About 10 mi of the line.
Sandstone. Age: Late Ordovician to Silurian, 428 to 459 million years old. About 8 mi of the line.
Slate. Age: Neoproterozoic to Ordovician, 445 to 1,000 million years old. About 2 mi of the line.
Mafic-volcanic. Age: Neoproterozoic to Ordovician, 445 to 1,000 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.
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 Topsham reaches the Atlantic Ocean by way of the Androscoggin and the Kennebec: about 30 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Topsham; river miles along the main stem, rounded.
Topsham has a warm-summer humid continental climate. Summer afternoons average 79° in July; winter nights fall to about 7° in January. A normal year brings about 78 inches of snow; with the rain, that comes to about 50 inches of water.
On November 14 Topsham normally reaches 46° and falls to 27°. The record high is 64°, in 2010; the record low 6°, in 2019. The most rain on this date, 1.02 in, fell in 2018.
Normals 1991–2020 and records since 1993 at Durham, 8 miles northwest. NOAA, through RCC-ACIS.
