The Hornsby 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.
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Partly cloudy; warmer
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12° on Nov. 13, 2019, the coldest reading for this week of the year since 1893. Next is 13° in 1940.
Hornsby’s center stands about 390 ft above sea level. Within three miles the land runs from 350 ft to 590 ft, a difference of 240 ft: rolling country. The highest named summit within 15 miles is Laurel Hill, about 660 ft, 9 miles northeast.
Under the town center the state geologic map shows Midway Group including Porters Creek Clay and Clayton Formation, from the Tertiary, 2.6 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 61×. 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: Tertiary, 2.6 to 66 million years old. About 10 mi of the line.
Clay. Age: Tertiary, 2.6 to 66 million years old. About 9 mi of the line.
Fine-detrital, coarse-detrital. Age: Quaternary, less than 2.6 million years old. About 4 mi of the line.
Fine-detrital, coarse-detrital. Age: Tertiary to Quaternary, less than 66 million years old. About 2 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 Hornsby reaches the Gulf of America by way of Wade Creek, Porters Creek, Cypress Creek and the Mississippi: about 940 river miles.
800 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Hornsby; river miles along the main stem, rounded.
Hornsby has a humid subtropical climate. Summer afternoons average 90° in July; winter nights fall to about 28° in January. About 56 inches of rain fall in a normal year, with about 2 inches of snow.
On November 14 Hornsby normally reaches 62° and falls to 37°. The record high is 81°, in 1931; the record low 13°, in 2019. The most rain on this date, 3.09 in, fell in 1957.
Normals 1991–2020 and records since 1893 at Bolivar Water Works, 9 miles west-northwest. NOAA, through RCC-ACIS.
