Sinkhole risk in Okanogan County, WA: No soluble rock mapped

No soluble rock mapped

No soluble bedrock mapped.

On soluble rock: under 1%
At or near the surface: under 1%
Buried under cover: 0%

What this means before you buy

No soluble bedrock is mapped here, so natural sinkholes are unlikely. Collapses from broken pipes or old mines are a separate risk.

That works out to roughly 37 of Okanogan County's 5,266 square miles on soluble rock, 37 of them with the rock at or near the surface. With about 44,942 residents (9 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 296 map points about 4.2 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Okanogan County

The nearest county rated sinkhole country is Emery County, UT, about 797 miles southeast. 5 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Ferry County, WA 56 mi east · under 1% at surface
Douglas County, WA 56 mi south · 0% at surface
Chelan County, WA 62 mi southwest · 0% at surface
Stevens County, WA 87 mi east · 3% at surface
Lincoln County, WA 91 mi southeast · 0% at surface
Grant County, WA 93 mi south · 0% at surface

Which formation it is

The largest mapped soluble unit here is the Triassic sedimentary rocks, undivided (limestone), Triassic with some Permian in age, covering about under 1% of the county.

Against the rest of Washington

Okanogan County ranks 4 of 39 in Washington for soluble rock at the surface, and sits above 54% of US counties on that measure.