Sinkhole risk in Webster County, MO: Sinkhole country

Sinkhole country

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

On soluble rock: 100%
At or near the surface: 100%
Buried under cover: 0%

What this means before you buy

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

That works out to roughly 593 of Webster County's 593 square miles on soluble rock, 593 of them with the rock at or near the surface. With about 42,041 residents (71 per square mile), there is effectively nowhere in the county off the soluble rock, town or country. The figures come from 369 map points about 1.3 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Webster County

The closest county with no soluble rock mapped is Van Buren County, AR, about 119 miles south. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Wright County, MO 22 mi east · 100% at surface
Greene County, MO 26 mi west · 97% at surface
Christian County, MO 28 mi southwest · 98% at surface
Dallas County, MO 29 mi north · 100% at surface
Laclede County, MO 30 mi northeast · 100% at surface
Douglas County, MO 30 mi southeast · 100% at surface

The rock underneath

The largest mapped soluble unit here is the Smithville Dolomite, Powell Dolomite, Cotter Dolomite, Jefferson City Dolomite (dolostone (dolomite)), Early Ordovician-Ibexian Series in age, covering about 52% of the county. Next is the Kinderhookian Series at 40%.

Against the rest of Missouri

Webster County ranks 19 of 115 in Missouri for soluble rock at the surface, and sits above 99% of US counties on that measure.