The Polk Centre 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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Chance of showers
69° on Nov. 17, 1953, the hottest reading for this week of the year since 1913. Next is 65° in 1939.
Polk Centre’s center stands about 1,000 ft above sea level. Within three miles the land runs from 990 ft to 1,040 ft, a difference of 50 ft: nearly flat ground.
Under the town center the state geologic map shows Granodiorite to hornblende diorite, locally magmatically foliated (granodiorite, diorite), from the Neoarchean, 2.5 to 2.8 billion years old.
The section below crosses 3 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 64×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Granodiorite, diorite. Age: Neoarchean, 2.5 to 2.8 billion years old. About 22 mi of the line.
Metabasalt, greenstone. Age: Neoarchean, 2.5 to 2.8 billion years old. About 1 mi of the line.
Gabbro, peridotite, pyroxenite. Age: Neoarchean, 2.5 to 2.8 billion years old. About 0.4 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 Polk Centre reaches Hudson Bay by way of the Black River, the Red Lake, the Red River of the North and the Nelson: about 1,040 river miles. Past the border it runs north through Canada to Hudson Bay.
Lake on the way: Lake Winnipeg.
400 miles of the trip are on the Nelson.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Polk Centre; river miles along the main stem, rounded.
Polk Centre has a warm-summer humid continental climate. Summer afternoons average 79° in July; winter nights fall to about −3° in January. A normal year brings about 50 inches of snow; with the rain, that comes to about 24 inches of water.
On November 14 Polk Centre normally reaches 36° and falls to 20°. The record high is 65°, in 1939; the record low −18°, in 1919. The most rain on this date, 1.65 in, fell in 1928.
Normals 1991–2020 and records since 1913 at Red Lake Falls, 10 miles southeast. NOAA, through RCC-ACIS.
