Sinkhole risk in Avery County, NC: 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%

The next step for one property

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

That works out to roughly 7 of Avery County's 247 square miles on soluble rock, 7 of them with the rock at or near the surface. With about 17,811 residents (72 per square mile), homes are spread across towns and farmland, and a mapped unit may or may not reach the developed parts. The figures come from 493 map points about 0.7 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Avery County

The nearest county rated sinkhole country is Washington County, TN, about 36 miles northwest, close enough that the same rock may run under the county line. 2 of the 6 closest counties land in the same band; the ground changes quickly around here.

Mitchell County, NC 14 mi west · 0% at surface
Watauga County, NC 16 mi northeast · 5% at surface
Carter County, TN 19 mi northwest · 25% at surface
Caldwell County, NC 24 mi east · under 1% at surface
Yancey County, NC 25 mi southwest · 0% at surface
Burke County, NC 26 mi southeast · 1% at surface

Which formation it is

The largest mapped soluble unit here is the Chilhowee Group, Grandfather Mountain Formation; Metasiltstone (metasedimentary rock), Late Proterozoic in age, covering about 3% of the county.

Against the rest of North Carolina

Avery County ranks 54 of 100 in North Carolina for soluble rock at the surface, and sits above 60% of US counties on that measure.