The Port Gibson 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.
7.72 inches of rain fell in two days, the most for this week of the year since records began in 1893. The next wettest, 5.37 inches, fell in 1929.
Port Gibson’s center stands about 130 ft above sea level. Within three miles the land runs from 80 ft to 330 ft, a difference of 250 ft: rolling country. The highest named summit within 15 miles is Blue Hill, about 490 ft, 15 miles south-southeast.
Under the town center the state geologic map shows Catahoula formation (sand), from the Miocene, 5.3 to 23 million years old.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 56×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sand. Age: Miocene, 5.3 to 23 million years old. About 24 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 Port Gibson reaches the Gulf of America by way of the Little Bayou Pierre, the Bayou Pierre and the Mississippi: about 430 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Port Gibson; river miles along the main stem, rounded.
Port Gibson has a humid subtropical climate. Summer afternoons average 93° in July; winter nights fall to about 36° in January. About 56 inches of rain fall in a normal year.
On November 14 Port Gibson normally reaches 69° and falls to 43°. The record high is 89°, in 1921; the record low 20°, in 1907. The most rain on this date, 2.93 in, fell in 1957.
Normals 1991–2020 and records since 1893 at Port Gibson 1 NE, 2 miles north-northeast. NOAA, through RCC-ACIS.