When homes, roads, businesses, and other structures were built throughout southeast Minnesota, sinkholes were far from the minds of the builders. The ground tested sound at the time the structure was built, but that was according to the standards of the time.
As we have all seen in the news in recent days, sinkholes have swallowed cars, entire homes, and much more, resulting in serious injury or death.
There have not been any serious sinkholes in southeast Minnesota recently, but that doesn’t mean they are not hanging out below the landscape.
The Minnesota Department of Natural Resources says there are approximately 10,000 sinkholes that have been tracked down in the southeast section of the state, but it is difficult to know exactly how many there are.
It is impossible to know exactly how many there are, as the department doesn’t have the resources to go out and search for them. They don’t have the manpower to make it happen.
As for how common sinkholes are in Minnesota, they are everywhere. They are common because of soluble dolomite and limestone, which wears away as water runs through the soil and reacts with the gasses within the soil that is produced by the plant roots and organic matter that is rotting away. The water mixed with carbonic acid makes the stone erode away. It is not just because limestone collapses. It is a much more complicated process than that. Once there is no soil, all that is left is air where the soil once was. Eventually, the ground weighs it down and it collapses, making the sinkhole happen. This creates a dangerous and even deadly scenario as was seen in the case of Jeff Bush who was killed in Florida when his home was swallowed by a sinkhole.
As for sinkholes in Minnesota, many have been seen. In regards to sinkholes in roadways, MnDOT is taking a proactive approach in stopping them before they become an issue. When a project is being performed, the county inspects culverts to ensure they are strong. If piping needs to be tied, they do it during the road project so they can avoid digging up the roadway later. And if a problem would occur with the roadway, the county is to address it as soon as possible before it becomes a deadly issue.
Nonetheless, there are times when the sinkholes are not foreseen, such as some of the street collapses that occurred in 2012. An evaluation of those sinkholes shows that the ones in Minnesota are large because of the dynamic landscape. As for prevention, measures are being taken to increase safety.