SinkholeOdds

Sinkhole risk in Sumner County, KS: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock
20%
At or near the surface
20%
Buried under cover
0%

The next step for one property

Check the parcel against your state survey sinkhole map, and ask for an inspection if cracks, depressions or sticking doors show up.

That works out to roughly 238 of Sumner County's 1,182 square miles on soluble rock, 238 of them with the rock at or near the surface. With about 22,336 residents (19 per square mile), much of the land is open, and the mapped rock may sit far from where people actually live. The figures come from 393 map points about 1.7 miles apart, so a pocket smaller than that can be missed or overstated.

Read next: why gypsum and salt move faster than limestone, and the signs to look for and how an inspection works.

Counties around Sumner County

The nearest county rated sinkhole country is Harper County, KS, about 32 miles west, close enough that the same rock may run under the county line. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

What Sumner County is built on

The largest mapped soluble unit here is the Sumner Group (shale), Late Permian - Cimarronian in age, covering about 20% of the county.

20% of the county sits on gypsum or salt, which dissolves in years rather than millennia. That share matters more than its size suggests.

The county also lies over the Permian Basin, Anadarko Basin,Dalhart Basin, Palo Duro Basin, a deep salt or gypsum basin. Deep beds rarely cause surface collapse on their own, but wells and mining into them have.

Against the rest of Kansas

Sumner County ranks 56 of 105 in Kansas for soluble rock at the surface, and sits above 74% of US counties on that measure.