SinkholeOdds

Sinkhole risk in Pembina County, ND: 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
11%
At or near the surface
0%
Buried under cover
11%

What to do about a house in Pembina County

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

That works out to roughly 122 of Pembina County's 1,119 square miles on soluble rock. With about 6,588 residents (6 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 375 map points about 1.7 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: why the 11% under cover still counts, and how these percentages are measured.

Counties around Pembina County

The nearest county rated sinkhole country is Boyd County, NE, about 410 miles south. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Which formation it is

The largest mapped soluble unit here is the Ordovician rocks (limestone), Ordovician in age, covering about 8% of the county. Next is the Niobrara and Carlile Formations, Undivided at 3%.

Against the rest of North Dakota

Pembina County ranks 37 of 53 in North Dakota for soluble rock at the surface, and sits above 0% of US counties on that measure.