SinkholeOdds

Sinkhole risk in Clark County, NV: Pockets of it

Pockets of it

Soluble rock at the surface or under thin cover in part of the county.

On soluble rock
29%
At or near the surface
29%
Buried under cover
0%

The next step for one property

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 2,320 of Clark County's 7,892 square miles on soluble rock, 2,320 of them with the rock at or near the surface. With about 2,398,871 residents (304 per square mile), homes are spread across towns and farmland, and a mapped unit may or may not reach the developed parts. The figures come from 245 map points about 5.7 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 the signs to look for and how an inspection works.

Counties around Clark County

The nearest county rated sinkhole country is Emery County, UT, about 304 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 Clark County is built on

The largest mapped soluble unit here is the Limestone and sparse dolomite, siltstone, and sandstone (limestone), Mississippian to Early Permian in age, covering about 9% of the county. Next is the Tuffaceous sedimentary rocks at 7%.

4% 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 Virgina Valley, 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 Nevada

Clark County ranks 3 of 17 in Nevada for soluble rock at the surface, and sits above 79% of US counties on that measure.