The Grand Coteau 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
Chance of showers; warmer
Showers likely
Mostly sunny; warmer
Partly cloudy
Mostly sunny
Mostly sunny
8.02 inches of rain fell in two days, the most for this week of the year since records began in 1893. The next wettest, 5.17 inches, fell in 2000.
Grand Coteau’s center stands about 70 ft above sea level. Within three miles the land runs from 20 ft to 90 ft, a difference of 70 ft: gently rolling country.
Under the town center the state geologic map shows Prairie Terraces (clay, silt, sand), from the Pleistocene, less than 2.6 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 64×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Clay, silt, sand. Age: Pleistocene, less than 2.6 million years old. About 12 mi of the line.
Clay. Age: Holocene, less than 12,000 years old. About 6 mi of the line.
Silt, clay. Age: Holocene, less than 12,000 years old. About 6 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 Grand Coteau reaches the Gulf of America by way of the Bayou Bourbeux, the Bayou Fusilier, the Vermilion and Onion Bayou: about 80 river miles.
70 miles of the trip are on the Vermilion.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Grand Coteau; river miles along the main stem, rounded.
Grand Coteau has a humid subtropical climate. Summer afternoons average 92° in August; winter nights fall to about 43° in January. About 63 inches of rain fall in a normal year.
On November 14 Grand Coteau normally reaches 72° and falls to 50°. The record high is 87°, in 1951; the record low 29°, in 1911. The most rain on this date, 3.22 in, fell in 1989.
Normals 1991–2020 and records since 1893 at Lafayette Regional Airport, 16 miles south-southeast. NOAA, through RCC-ACIS.
