The Folsom 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.
Mostly sunny
Mostly sunny; warmer
Mostly sunny
Partly cloudy
Partly cloudy
Partly cloudy; cooler
Showers likely
74° on Nov. 15, 1953, the hottest reading for this week of the year since 1931. Next is 74° in 2001.
Folsom’s center stands about 1,150 ft above sea level. Within three miles the land runs from 960 ft to 1,170 ft, a difference of 210 ft: rolling country.
Under the town center the state geologic map shows Undifferentiated (conglomerate, sandstone, mudstone), from the Late Cretaceous, 72 to 100 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 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.
Conglomerate, sandstone, mudstone. Age: Late Cretaceous, 72 to 100 million years old. About 15 mi of the line.
Shale, bentonite. Age: Late Cretaceous, 66 to 100 million years old. About 6 mi of the line.
Shale. Age: Late Cretaceous, 66 to 100 million years old. About 2 mi of the line.
Chalk, marlstone, shale. Age: Late Cretaceous, 66 to 100 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.
Folsom straddles the Laurentian Divide. Rain on the northwest side runs to Hudson Bay; most of the rest goes to the Gulf of America.
From the center of town, a raindrop reaches the Gulf of America by way of Big Stone Lake, the Minnesota and the Mississippi: about 2,180 river miles. One that lands on the northwest side reaches Hudson Bay by way of Steer Creek, the Bois de Sioux, the Red River of the North and the Nelson: about 1,250 river miles. Past the border it runs north through Canada to Hudson Bay.
Lakes on the way: Big Stone Lake and Lake Pepin.
1,750 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Folsom; river miles along the main stem, rounded.
Folsom has a warm-summer humid continental climate. Summer afternoons average 83° in July; winter nights fall to about 4° in January. A normal year brings about 36 inches of snow; with the rain, that comes to about 23 inches of water.
On November 14 Folsom normally reaches 42° and falls to 23°. The record high is 69°, in 1990; the record low −7°, in 2014. The most rain on this date, 0.86 in, fell in 1947.
Normals 1991–2020 and records since 1931 from the Sisseton Area threaded record (Sisseton Municipal Airport, 10 miles west-northwest). NOAA, through RCC-ACIS.
