The Port Allen 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
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Mostly sunny; warmer
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22° on Nov. 15, 1940, the coldest reading for this week of the year since 1892. Next is 24° in 1908.
Port Allen’s center stands about 30 ft above sea level. Within three miles the land runs from 10 ft to 70 ft, a difference of 60 ft: gently rolling country.
Under the town center the state geologic map shows Natural Levees (silt, clay), from the Holocene, less than 12,000 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.
Silt, clay. Age: Holocene, less than 12,000 years old. About 14 mi of the line.
Clay, silt, sand. Age: Pleistocene, less than 2.6 million years old. About 8 mi of the line.
Clay. Age: Holocene, less than 12,000 years old. About 1 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 Allen reaches the Gulf of America by way of the Lower Grand, the Chopin Chute, the Bayou Grosbec, Little Texas Bayou, Fourmile Bayou, the Bayou Cherami, the Bayou Chene and the Lower Atchafalaya: about 100 river miles.
Lakes on the way: Lake Verret and Lake Palourde.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Port Allen; river miles along the main stem, rounded.
Port Allen has a humid subtropical climate. Summer afternoons average 92° in July; winter nights fall to about 42° in January. About 62 inches of rain fall in a normal year.
On November 14 Port Allen normally reaches 71° and falls to 48°. The record high is 85°, in 1951; the record low 26°, in 1907. The most rain on this date, 2.00 in, fell in 1909.
Normals 1991–2020 and records since 1892 from the Baton Rouge Area threaded record (Baton Rouge Metro Airport, 7 miles north-northeast). NOAA, through RCC-ACIS.
