Sinkhole risk in Vernon County, WI: Sinkhole country

Sinkhole country

Soluble rock at or near the surface across much of the county.

On soluble rock: 64%
At or near the surface: 63%
Buried under cover: 1%

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 507 of Vernon County's 792 square miles on soluble rock, 499 of them with the rock at or near the surface. With about 31,351 residents (40 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 308 map points about 1.6 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: the signs to look for and how an inspection works, and how these percentages are measured.

Counties around Vernon County

The closest county with no soluble rock mapped is Juneau County, WI, about 42 miles northeast. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Richland County, WI 25 mi southeast · 41% at surface
Crawford County, WI 25 mi south · 71% at surface
La Crosse County, WI 26 mi northwest · 22% at surface
Monroe County, WI 26 mi northeast · 16% at surface
Houston County, MN 34 mi west · 28% at surface
Allamakee County, IA 36 mi southwest · 25% at surface

The rock underneath

The largest mapped soluble unit here is the Prairie du Chien Group (shale), Lower Ordovician in age, covering about 45% of the county. Next is the Ancell Group at 13%.

Against the rest of Wisconsin

Vernon County ranks 5 of 72 in Wisconsin for soluble rock at the surface, and sits above 91% of US counties on that measure.