The Dunstan 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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73° on Nov. 12, 2022, the hottest reading for this week of the year since 1871. Next is 72° in 1896.
Dunstan’s center stands about 60 ft above sea level. Within three miles the land runs from 0 ft to 210 ft, a difference of 210 ft: rolling country. The highest named summit within 15 miles is Breakheart Hill, about 590 ft, 14 miles northwest.
Under the town center the state geologic map shows Ordovician - Precambrian Z Scarboro and Diamond Island formations (metasedimentary), from the Neoproterozoic to Ordovician, 445 to 1,000 million years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 52×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sandstone. Age: Late Ordovician to Silurian, 428 to 459 million years old. About 6 mi of the line.
Slate. Age: Neoproterozoic to Ordovician, 445 to 1,000 million years old. About 4 mi of the line.
Metasedimentary. Age: Neoproterozoic to Ordovician, 445 to 1,000 million years old. About 3 mi of the line.
Schist, slate. Age: Silurian, 428 to 445 million years old. About 1 mi of the line.
Felsic-volcanic. Age: Late Ordovician to Silurian, 428 to 459 million years old. About 0.4 mi of the line.
Marble, calc-silicate-rock, metasedimentary. Age: Silurian, 428 to 445 million years old. About 0.3 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 Dunstan reaches the Atlantic Ocean by way of the Scarborough: about 4 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Dunstan; river miles along the main stem, rounded.
Dunstan has a warm-summer humid continental climate. Summer afternoons average 80° in July; winter nights fall to about 16° in January. A normal year brings about 69 inches of snow; with the rain, that comes to about 48 inches of water.
On November 14 Dunstan normally reaches 49° and falls to 32°. The record high is 69°, in 1973; the record low 12°, in 1986. The most rain on this date, 5.03 in, fell in 2009.
Normals 1991–2020 and records since 1871 from the Portland Area threaded record (Portland Jetport, 7 miles northeast). NOAA, through RCC-ACIS.
