The Welch 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.
5° on Nov. 15, 2014, the coldest reading for this week of the year since 1948. Next is 5° in 2019.
Welch’s center stands about 770 ft above sea level. Within three miles the land runs from 710 ft to 1,060 ft, a difference of 350 ft: rolling country. The highest named summit within 15 miles is Negro Hill, about 1,130 ft, 14 miles north-northeast.
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 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.
Dolostone, sandstone. Age: Early Ordovician, 471 to 487 million years old. About 11 mi of the line.
Sandstone, siltstone, shale. Age: Cambrian, 487 to 497 million years old. About 6 mi of the line.
Shale, limestone, sandstone. Age: Middle Ordovician to Late Ordovician, 445 to 471 million years old. About 5 mi of the line.
Dolostone. Age: Early Ordovician, 471 to 487 million years old. About 2 mi of the line.
Limestone, dolostone. Age: Late Ordovician, 445 to 459 million years old. About 0.8 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 Welch reaches the Gulf of America by way of the Vermillion, Vermillion Slough 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 Welch; river miles along the main stem, rounded.
Welch has a hot-summer humid continental climate. Summer afternoons average 82° in July; winter nights fall to about 6° in January. About 32 inches of rain fall in a normal year.
On November 14 Welch normally reaches 43° and falls to 27°. The record high is 69°, in 1999; the record low 8°, in 2018. The most rain on this date, 0.98 in, fell in 1951.
Normals 1991–2020 and records since 1948 at Red Wing Dam 3, 7 miles east-northeast. NOAA, through RCC-ACIS.