The Osage 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
Mostly sunny; warmer
Mostly sunny
Partly cloudy
Mostly sunny; cooler
Partly cloudy
Chance of showers
72° on Nov. 14, 1999, the hottest reading for this week of the year since 1908. Next is 71° in 1989.
Osage’s center stands about 4,310 ft above sea level. Within three miles the land runs from 4,110 ft to 4,550 ft, a difference of 440 ft: hilly country. The highest named summit within 15 miles is Sweetwater Mountain, about 6,440 ft, 12 miles east-northeast.
Under the town center the state geologic map shows Greenhorn Formation and Belle Fourche and Mowry Shale, from the Early Cretaceous to Late Cretaceous, 66 to 145 million years old.
The section below crosses 10 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 8×. 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, claystone. Age: Late Jurassic to Early Cretaceous, 100 to 164 million years old. About 4 mi of the line.
Sandstone, shale. Age: Late Cretaceous, 66 to 100 million years old. About 4 mi of the line.
Shale. Age: Late Cretaceous, 72 to 78 million years old. About 3 mi of the line.
Shale. Age: Early Cretaceous to Late Cretaceous, 66 to 145 million years old. About 3 mi of the line.
Sandstone, shale. Age: Early Cretaceous, 100 to 145 million years old. About 3 mi of the line.
Sandstone, shale, dolostone. Age: Middle Jurassic to Late Jurassic, 145 to 175 million years old. About 2 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 4 smaller units along the line are not listed.
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 Osage reaches the Gulf of America by way of Turner Creek, Beaver Creek, the Cheyenne, the Missouri and the Mississippi: about 2,710 river miles.
Lakes on the way: Lake Oahe, Lake Sharpe, 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 Osage; river miles along the main stem, rounded.
Osage has a cold semi-arid climate. Summer afternoons average 87° in July; winter nights fall to about 10° in January. A normal year brings about 46 inches of snow; with the rain, that comes to about 16 inches of water.
On November 14 Osage normally reaches 44° and falls to 20°. The record high is 72°, in 1999; the record low −22°, in 1959. The most rain on this date, 0.27 in, fell in 2008.
Normals 1991–2020 and records since 1908 at Upton, 12 miles northwest. NOAA, through RCC-ACIS.
