The Stephan 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.
Partly cloudy
Sunny; warmer
Mostly sunny
Partly cloudy
Partly cloudy
Partly cloudy
Showers likely
77° on Nov. 16, 1999, the hottest reading for this week of the year since 1965. Next is 74° in 1990.
Stephan’s center stands about 1,830 ft above sea level. Within three miles the land runs from 1,760 ft to 1,960 ft, a difference of 200 ft: rolling country.
Under the town center the state geologic map shows Pierre Shale (shale, bentonite), from the Late Cretaceous, 66 to 100 million years old.
The section below crosses 2 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 25×. 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, bentonite. Age: Late Cretaceous, 66 to 100 million years old. About 24 mi of the line.
Chalk, marlstone, shale. Age: Late Cretaceous, 66 to 100 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 Stephan reaches the Gulf of America by way of West Fork Elm Creek, Elm Creek, Crow Creek, the Missouri and the Mississippi: about 2,210 river miles.
Lakes on the way: Lake Francis Case and Lewis and Clark Lake.
1,170 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Stephan; river miles along the main stem, rounded.
Stephan has a dry-winter hot-summer continental climate. Summer afternoons average 87° in July; winter nights fall to about 7° in January. A normal year brings about 19 inches of snow; with the rain, that comes to about 20 inches of water.
On November 14 Stephan normally reaches 47° and falls to 24°. The record high is 73°, in 2016; the record low −3°, in 2014. The most rain on this date, 0.38 in, fell in 1988.
Normals 1991–2020 and records since 1965 at Lake Sharpe Project, 13 miles south, 370 ft lower. NOAA, through RCC-ACIS.
