The Riverdale 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
Partly cloudy
Mostly cloudy
Chance of showers; cooler
Mostly cloudy
Chance of showers
71° on Nov. 13, 1999, the hottest reading for this week of the year since 1954. Next is 68° in 2001.
Riverdale’s center stands about 1,970 ft above sea level. Within three miles the land runs from 1,680 ft to 1,980 ft, a difference of 300 ft: rolling country.
Under the town center the state geologic map shows Sentinel Butte Formation (siltstone, claystone, sandstone), from the Paleocene, 56 to 66 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 40×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Siltstone, claystone, sandstone. Age: Paleocene, 56 to 66 million years old. About 23 mi of the line.
Claystone, siltstone. Age: Paleocene, 56 to 66 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.
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 Riverdale reaches the Gulf of America by way of the Missouri and the Mississippi: about 2,550 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 Riverdale; river miles along the main stem, rounded.
Riverdale has a warm-summer humid continental climate. Summer afternoons average 82° in July; winter nights fall to about 1° in January. A normal year brings about 39 inches of snow; with the rain, that comes to about 18 inches of water.
On November 14 Riverdale normally reaches 37° and falls to 19°. The record high is 67°, in 2001; the record low −13°, in 1959. The most rain on this date, 0.15 in, fell in 1955.
Normals 1991–2020 and records since 1954 at Underwood, 11 miles east-southeast. NOAA, through RCC-ACIS.
