Sinkhole risk in Pocahontas 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: 3%
At or near the surface: 0%
Buried under cover: 3%

What to do about a house in Pocahontas County

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

That works out to roughly 19 of Pocahontas County's 577 square miles on soluble rock. With about 7,006 residents (12 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 391 map points about 1.2 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: how these percentages are measured, and the warning signs that apply anywhere.

Counties around Pocahontas County

The nearest county rated sinkhole country is Knox County, NE, about 163 miles west. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Buena Vista County, IA 24 mi west · 0% at surface
Palo Alto County, IA 24 mi north · 0% at surface
Calhoun County, IA 24 mi south · 0% at surface
Humboldt County, IA 24 mi east · 0% at surface
Sac County, IA 32 mi southwest · 0% at surface
Webster County, IA 33 mi southeast · 0% at surface

What Pocahontas County is built on

The largest mapped soluble unit here is the Kinderhook Series (limestone), Early Mississippian in age, covering about 3% of the county. Next is the Meramec Series at under 1%.

Against the rest of Iowa

Pocahontas County ranks 78 of 99 in Iowa for soluble rock at the surface, and sits above 0% of US counties on that measure.