The Dennison 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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Showers likely
73° on Nov. 16, 1953, the hottest reading for this week of the year since 1895. Next is 72° in 2012.
Dennison’s center stands about 1,030 ft above sea level. Within three miles the land runs from 920 ft to 1,150 ft, a difference of 230 ft: rolling country.
Under the town center the state geologic map shows Middle and Upper Ordovician (shale, limestone, sandstone), from the Middle Ordovician to Late Ordovician, 445 to 471 million 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 42×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Shale, limestone, sandstone. Age: Middle Ordovician to Late Ordovician, 445 to 471 million years old. About 19 mi of the line.
Dolostone, sandstone. Age: Early Ordovician, 471 to 487 million years old. About 4 mi of the line.
Limestone, dolostone. Age: Late Ordovician, 445 to 459 million years old. About 0.5 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 Dennison reaches the Gulf of America by way of Prairie Creek, the Cannon and the Mississippi: about 1,810 river miles.
Lake on the way: Lake Pepin.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Dennison; river miles along the main stem, rounded.
Dennison has a warm-summer humid continental climate. Summer afternoons average 81° in July; winter nights fall to about 4° in January. A normal year brings about 44 inches of snow; with the rain, that comes to about 35 inches of water.
On November 14 Dennison normally reaches 43° and falls to 24°. The record high is 70°, in 1990; the record low −5°, in 1959. The most rain on this date, 0.90 in, fell in 1909.
Normals 1991–2020 and records since 1895 at Zumbrota, 20 miles east-southeast. NOAA, through RCC-ACIS.
