Sinkhole risk in Crowley 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: 4%
At or near the surface: 4%
Buried under cover: 0%

What this means before you buy

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

That works out to roughly 31 of Crowley County's 787 square miles on soluble rock, 31 of them with the rock at or near the surface. With about 5,600 residents (7 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 375 map points about 1.4 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: why gypsum and salt move faster than limestone, and how these percentages are measured.

Counties around Crowley County

The nearest county rated sinkhole country is Clark County, KS, about 229 miles east. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Otero County, CO 29 mi south · 42% at surface
Pueblo County, CO 40 mi west · 45% at surface
Bent County, CO 46 mi southeast · 44% at surface
Lincoln County, CO 50 mi north · 0% at surface
El Paso County, CO 55 mi northwest · 2% at surface
Kiowa County, CO 55 mi east · 30% at surface

The rock underneath

The largest mapped soluble unit here is the Niobrara Fm (shale), Cretaceous in age, covering about 4% of the county.

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 Colorado

Crowley County ranks 23 of 64 in Colorado for soluble rock at the surface, and sits above 61% of US counties on that measure.