Sinkhole risk in Wallowa County, OR: 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: 2%
At or near the surface: 2%
Buried under cover: 0%

What to do about a house in Wallowa County

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

That works out to roughly 57 of Wallowa County's 3,146 square miles on soluble rock, 57 of them with the rock at or near the surface. With about 7,522 residents (2 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 276 map points about 3.4 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Wallowa County

The nearest county rated sinkhole country is Emery County, UT, about 562 miles southeast. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.

Asotin County, WA 41 mi north · 0% at surface
Union County, OR 44 mi southwest · under 1% at surface
Nez Perce County, ID 55 mi north · 3% at surface
Lewis County, ID 58 mi northeast · under 1% at surface
Columbia County, WA 60 mi northwest · 0% at surface
Garfield County, WA 60 mi north · 0% at surface

Which formation it is

The largest mapped soluble unit here is the Marine sedimentary rocks (Upper Triassic? and Upper and Middle Triassic) (argillite), Early Triassic in age, covering about 1% of the county. Next is the Sedimentary rocks (Jurassic and Upper Triassic) at under 1%.

Against the rest of Oregon

Wallowa County ranks 6 of 36 in Oregon for soluble rock at the surface, and sits above 57% of US counties on that measure.