Sinkhole risk in Ouray County, CO: No soluble rock mapped

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 3 of Ouray County's 541 square miles on soluble rock, 3 of them with the rock at or near the surface. With about 5,197 residents (10 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 525 map points about 1.0 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: how these percentages are measured, and the warning signs that apply anywhere.

Counties around Ouray County

The nearest county rated sinkhole country is Emery County, UT, about 169 miles west. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

• San Juan County, CO 27 mi south · 1% at surface
• Montrose County, CO 31 mi northwest · 1% at surface
• Hinsdale County, CO 32 mi southeast · under 1% at surface
• San Miguel County, CO 36 mi west · under 1% at surface
• Dolores County, CO 49 mi southwest · 0% at surface
• Delta County, CO 49 mi north · 0% at surface

The rock underneath

The largest mapped soluble unit here is the Hermosa Fm (sandstone), Pennsylvanian in age, covering about under 1% of the county. Next is the Hermosa Fm at under 1%.

Against the rest of Colorado

Ouray County ranks 36 of 64 in Colorado for soluble rock at the surface, and sits above 53% of US counties on that measure.

• Pueblo County 45%
• Bent County 44%
• Otero County 42%
• Prowers County 35%
• Kiowa County 30%