Sinkhole risk in Beckham County, OK: Sinkhole country

Sinkhole country

Fast-dissolving gypsum or salt beds under a large part of the county.

On soluble rock: 32%
At or near the surface: 32%
Buried under cover: 0%

The next step for one property

Get a sinkhole or geotechnical inspection before buying, building or adding weight to a foundation.

That works out to roughly 288 of Beckham County's 902 square miles on soluble rock, 288 of them with the rock at or near the surface. With about 22,248 residents (25 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 301 map points about 1.7 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 Beckham County

The closest county with no soluble rock mapped is Hemphill County, TX, about 50 miles northwest. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Greer County, OK 25 mi south · 36% at surface
Roger Mills County, OK 30 mi north · 31% at surface
Wheeler County, TX 33 mi west · 25% at surface
Harmon County, OK 37 mi south · 77% at surface
Collingsworth County, TX 39 mi southwest · 59% at surface
Washita County, OK 39 mi east · 64% at surface

What Beckham County is built on

The largest mapped soluble unit here is the Blaine Formation (evaporite), Early Permian in age, covering about 12% of the county. Next is the Cloud Chief Formation at 8%.

32% 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 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 Oklahoma

Beckham County ranks 26 of 77 in Oklahoma for soluble rock at the surface, and sits above 80% of US counties on that measure.