SinkholeOdds

Sinkhole risk in Guthrie County, IA: 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
5%
At or near the surface
0%
Buried under cover
5%

What to do about a house in Guthrie County

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

That works out to roughly 32 of Guthrie County's 591 square miles on soluble rock. With about 10,774 residents (18 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 367 map points about 1.3 miles apart, so a pocket smaller than that can be missed or overstated.

Read next: why gypsum and salt move faster than limestone, and why the 5% under cover still counts.

Counties around Guthrie County

The nearest county rated sinkhole country is Clayton County, IA, about 181 miles northeast. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

What Guthrie County is built on

The largest mapped soluble unit here is the Kansas City Group (limestone), Late Pennsylvanian-Missouri Series in age, covering about 4% of the county. Next is the Marmaton Group at 2%.

The county also lies over the Forest City 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 Iowa

Guthrie County ranks 45 of 99 in Iowa for soluble rock at the surface, and sits above 0% of US counties on that measure.