Sinkhole risk in Yuma County, CO: 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: 7%
At or near the surface: 7%
Buried under cover: 0%

The next step for one property

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

That works out to roughly 168 of Yuma County's 2,364 square miles on soluble rock, 168 of them with the rock at or near the surface. With about 10,048 residents (4 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 410 map points about 2.4 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Yuma County

The nearest county rated sinkhole country is Harlan County, NE, about 160 miles east. None of the 6 closest counties land in the same band, so Yuma County stands out from its surroundings.

Cheyenne County, KS 40 mi east · 19% at surface
Dundy County, NE 41 mi east · 17% at surface
Phillips County, CO 41 mi north · 0% at surface
Washington County, CO 42 mi west · 0% at surface
Kit Carson County, CO 49 mi south · 0% at surface
Chase County, NE 53 mi northeast · 0% at surface

What Yuma County is built on

The largest mapped soluble unit here is the Ogallala Fm (sandstone), Tertiary in age, covering about 6% of the county. Next is the Pierre Shale--Upper unit at 2%.

2% 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 Northern Denver 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 Colorado

Yuma County ranks 14 of 64 in Colorado for soluble rock at the surface, and sits above 65% of US counties on that measure.