The Oak Grove 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.
3.24 inches of rain fell in two days, the most for this week of the year since records began in 1918. The next wettest, 2.10 inches, fell in 1940.
Oak Grove’s center stands about 1,030 ft above sea level. Within three miles the land runs from 670 ft to 1,080 ft, a difference of 410 ft: hilly country.
Under the town center the state geologic map shows Prairie du Chien Group (dolostone), from the Early Ordovician, 471 to 487 million years old.
The section below crosses 5 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 35×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Dolostone. Age: Early Ordovician, 471 to 487 million years old. About 8 mi of the line.
Sandstone. Age: Ordovician, 445 to 487 million years old. About 7 mi of the line.
Dolostone, sandstone. Age: Early Ordovician, 471 to 487 million years old. About 4 mi of the line.
Sandstone, siltstone, shale. Age: Cambrian, 487 to 497 million years old. About 4 mi of the line.
Dolostone. Age: Ordovician, 445 to 487 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 Oak Grove reaches the Gulf of America by way of the Big River and the Mississippi: about 1,790 river miles.
Lake on the way: Lake Pepin.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Oak Grove; river miles along the main stem, rounded.
Oak Grove has a warm-summer humid continental climate. Summer afternoons average 82° in July; winter nights fall to about 4° in January. About 34 inches of rain fall in a normal year.
On November 14 Oak Grove normally reaches 42° and falls to 24°. The record high is 71°, in 1990; the record low −8°, in 1940. The most rain on this date, 1.09 in, fell in 1951.
Normals 1991–2020 and records since 1918 at River Falls, 9 miles north-northeast. NOAA, through RCC-ACIS.