SinkholeOdds

Sinkhole risk in Sweetwater County, WY: 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
3%
Buried under cover
0%

What to do about a house in Sweetwater County

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

That works out to roughly 282 of Sweetwater County's 10,427 square miles on soluble rock, 282 of them with the rock at or near the surface. With about 41,273 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 364 map points about 5.4 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why gypsum and salt move faster than limestone, and how these percentages are measured.

Counties around Sweetwater County

The nearest county rated sinkhole country is Emery County, UT, about 207 miles southwest. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

What Sweetwater County is built on

The largest mapped soluble unit here is the Green River Formation: Wilkins Peak Member and Tipton Shale member or Tongue (mixed clastic/carbonate), Eocene in age, covering about 2% of the county. Next is the Green River Formation: Wilkins Peak Member at under 1%.

The county also lies over the Green River 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 Wyoming

Sweetwater County ranks 17 of 23 in Wyoming for soluble rock at the surface, and sits above 59% of US counties on that measure.