Sinkhole risk in Coffee County, AL: Mostly deep or small

Mostly deep or small

Some soluble rock, mostly deeply buried or in a small share of the county.

On soluble rock: 9%
At or near the surface: 2%
Buried under cover: 7%

What to do about a house in Coffee County

Sinkholes are uncommon here; watch for new depressions after heavy rain or leaking pipes.

That works out to roughly 60 of Coffee County's 679 square miles on soluble rock, 12 of them with the rock at or near the surface. With about 56,358 residents (83 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 387 map points about 1.3 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why the 7% under cover still counts, and how these percentages are measured.

Counties around Coffee County

The nearest county rated sinkhole country is Geneva County, AL, about 24 miles southeast, close enough that the same rock may run under the county line. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Dale County, AL 22 mi east · 7% at surface
Geneva County, AL 24 mi southeast · 51% at surface
Pike County, AL 28 mi north · 31% at surface
Covington County, AL 29 mi west · 4% at surface
Crenshaw County, AL 30 mi northwest · 30% at surface
Holmes County, FL 39 mi south · 66% at surface

The rock underneath

The largest mapped soluble unit here is the Jackson Group undifferentiated (clay or mud), Eocene in age, covering about 7% of the county. Next is the Jackson Group undifferentiated at 2%.

Against the rest of Alabama

Coffee County ranks 51 of 67 in Alabama for soluble rock at the surface, and sits above 57% of US counties on that measure.