Sinkhole risk in Chaffee County, CO: 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: 4%
At or near the surface: 4%
Buried under cover: 0%

What this means before you buy

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

That works out to roughly 42 of Chaffee County's 1,013 square miles on soluble rock, 42 of them with the rock at or near the surface. With about 20,780 residents (21 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 242 map points about 2.0 miles apart, so a pocket smaller than that can be missed or overstated.

Counties around Chaffee County

The nearest county rated sinkhole country is Emery County, UT, about 239 miles west. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Lake County, CO 33 mi north · 5% at surface
Park County, CO 41 mi northeast · 13% at surface
Gunnison County, CO 41 mi west · 2% at surface
Pitkin County, CO 47 mi northwest · 5% at surface
Saguache County, CO 49 mi south · 1% at surface
Fremont County, CO 51 mi east · 12% at surface

The rock underneath

The largest mapped soluble unit here is the Leadville Limestone, Williams Canyon Limestone, and one or more of: Fremont Limestone, Harding Sandstone, and Manitou Limestone (limestone), Mississippian-Ordovician in age, covering about 3% of the county. Next is the Evaporitic facies of Minturn And Belden Fms in South Park and southward at under 1%.

1% of the county sits on gypsum or salt, which dissolves in years rather than millennia. That share matters more than its size suggests.

Against the rest of Colorado

Chaffee County ranks 21 of 64 in Colorado for soluble rock at the surface, and sits above 62% of US counties on that measure.