Sinkhole risk in Colbert County, AL: Sinkhole country

Sinkhole country

Soluble rock at or near the surface across much of the county.

On soluble rock: 60%
At or near the surface: 60%
Buried under cover: 0%

The next step for one property

Get a sinkhole or geotechnical inspection before buying, building or adding weight to a foundation.

That works out to roughly 358 of Colbert County's 593 square miles on soluble rock, 358 of them with the rock at or near the surface. With about 58,785 residents (99 per square mile), homes are spread across towns and farmland, and a mapped unit may or may not reach the developed parts. The figures come from 277 map points about 1.5 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Colbert County

The closest county with no soluble rock mapped is Marion County, AL, about 39 miles south. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Lauderdale County, AL 16 mi northeast · 37% at surface
Franklin County, AL 18 mi south · 31% at surface
Tishomingo County, MS 25 mi west · 10% at surface
Lawrence County, AL 30 mi southeast · 60% at surface
Wayne County, TN 37 mi north · 15% at surface
Marion County, AL 39 mi south · 0% at surface

What Colbert County is built on

The largest mapped soluble unit here is the Tuscumbia Limestone (limestone), Mississippian in age, covering about 36% of the county. Next is the Pride Mountain Formation at 20%.

Against the rest of Alabama

Colbert County ranks 3 of 67 in Alabama for soluble rock at the surface, and sits above 90% of US counties on that measure.