The Altha 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.
Sunny
Mostly sunny; warmer
Mostly cloudy
Mostly sunny; warmer
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28° on Nov. 12, 2011, the coldest reading for this week of the year since 1950. Next is 28° in 2019.
Altha’s center stands about 210 ft above sea level. Within three miles the land runs from 60 ft to 240 ft, a difference of 180 ft: gently rolling country.
Under the town center the state geologic map shows Citronelle Formation (sand), from the Late Pliocene, 2.6 to 3.6 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 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.
Sand. Age: Late Pliocene, 2.6 to 3.6 million years old. About 16 mi of the line.
Sand, clay. Age: Middle Miocene to Early Pliocene, 3.6 to 16 million years old. About 4 mi of the line.
Clay. Age: Late Miocene, 5.3 to 12 million years old. About 2 mi of the line.
Sandstone, limestone. Age: Middle Miocene, 12 to 16 million years old. About 2 mi of the line.
Dolostone. Age: Early Miocene, 16 to 23 million 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 Altha reaches the Gulf of America by way of Hollis Branch, the Chipola and the Apalachicola: about 80 river miles.
55 miles of the trip are on the Chipola.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Altha; river miles along the main stem, rounded.
Altha has a humid subtropical climate. Summer afternoons average 92° in July; winter nights fall to about 41° in January. About 51 inches of rain fall in a normal year.
On November 14 Altha normally reaches 72° and falls to 47°. The record high is 85°, in 1955; the record low 29°, in 2013. The most rain on this date, 1.83 in, fell in 1957.
Normals 1991–2020 and records since 1950 at Marianna Municipal Airport, 19 miles north, 100 ft lower. NOAA, through RCC-ACIS.
