The Cumby 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.
4.23 inches of rain fell in two days, the most for this week of the year since records began in 1893. The next wettest, 3.14 inches, fell in 1978.
Cumby’s center stands about 640 ft above sea level. Within three miles the land runs from 540 ft to 640 ft, a difference of 100 ft: gently rolling country.
Under the town center the state geologic map shows Wills Point Formation (clay), from the Paleocene, 56 to 66 million years old.
The section below crosses 4 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. Age: Paleocene, 56 to 66 million years old. About 14 mi of the line.
Clay, sand. Age: Paleocene, 56 to 66 million years old. About 4 mi of the line.
Fine-detrital, coarse-detrital. Age: Holocene, less than 12,000 years old. About 4 mi of the line.
Clay, sand. Age: Late Cretaceous, 66 to 72 million years old. About 3 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 Cumby reaches the Gulf of America by way of Big Creek, Garrett Creek, Lake Fork Creek and the Sabine: about 470 river miles.
Lakes on the way: Toledo Bend Reservoir, Sabine Lake and Case Lake.
180 miles of the trip are on the Sabine.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Cumby; river miles along the main stem, rounded.
Cumby has a humid subtropical climate. Summer afternoons average 95° in August; winter nights fall to about 34° in January. About 46 inches of rain fall in a normal year.
On November 14 Cumby normally reaches 67° and falls to 44°. The record high is 87°, in 2005; the record low 22°, in 1986. The most rain on this date, 1.82 in, fell in 1970.
Normals 1991–2020 and records since 1893 at Sulphur Springs, 12 miles east, 140 ft lower. NOAA, through RCC-ACIS.