SinkholeOdds

Sinkhole risk in Wallace 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
23%
At or near the surface
23%
Buried under cover
0%

What to do about a house in Wallace County

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 209 of Wallace County's 914 square miles on soluble rock, 209 of them with the rock at or near the surface. With about 1,472 residents (2 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 402 map points about 1.5 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 Wallace County

The nearest county rated sinkhole country is Harlan County, NE, about 153 miles northeast. None of the 6 closest counties land in the same band, so Wallace County stands out from its surroundings.

What Wallace County is built on

The largest mapped soluble unit here is the Ogallala Formation (arkose), Miocene in age, covering about 13% of the county. Next is the Pierre Shale at 10%.

10% 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

Wallace County ranks 50 of 105 in Kansas for soluble rock at the surface, and sits above 76% of US counties on that measure.