The Lake Andes 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
Sunny
Partly cloudy
Partly cloudy
Partly cloudy; cooler
Showers likely
Lake Andes’s center stands about 1,480 ft above sea level. Within three miles the land runs from 1,410 ft to 1,810 ft, a difference of 400 ft: hilly country. The highest named summit within 15 miles is Scalp Butte, about 1,890 ft, 12 miles west-southwest.
Under the town center the state geologic map shows Niobrara Formation (chalk, marlstone, shale), from the Late Cretaceous, 66 to 100 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 36×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Chalk, marlstone, shale. Age: Late Cretaceous, 66 to 100 million years old. About 12 mi of the line.
Shale, bentonite. Age: Late Cretaceous, 66 to 100 million years old. About 10 mi of the line.
Fine-detrital, siltstone, conglomerate-sandstone. Age: Miocene to Pliocene, 2.6 to 23 million years old. About 0.9 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 Lake Andes reaches the Gulf of America by way of Garden Creek, the Missouri and the Mississippi: about 2,050 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 Lake Andes; river miles along the main stem, rounded.
