Study Examines Minnesota Landslides

A study has determined that nearly 500 landslides have happened in the Mankato, Minnesota, area in recent years.

Minnesota State University Earth Science Programs Director Phillip Larson with the help of students mapped out the area’s ravines, bluffs, nooks and crannies during the past three years. Their work determined where landslides have occurred, and what areas are more at risk for them.

“Everybody thinks of hillslopes and landslides and these sorts of big erosional issues as something that happens in mountains, right?” Larson said. “This is something that happens in Washington state, or California or Colorado, and not here. In reality, it turns out these are far more common here than anybody ever realized.”

The odds of property damage due to landslides are small, but area scientists believe those odds might grow with each passing year, The Free Press reported. A lot of the ground that makes up ravines and bluffs in the area is becoming more prone to erosion because of increasing rainfall and urban development.

“We could help make sure homeowners don’t lose their homes in the future,” said Missy Kohout, a Mankato State graduate student working on the project.

The Mankato-area work is part of a larger statewide study. Eight colleges and universities received a $500,000 state grant in 2016 to inventory geological activity around the state. Geologists are looking at thousands of examples of landscape failures from the Red River Valley through the Mississippi River Valley.

They hope the landslide inventory will lead to predictive landslide regulations similar to the ones found in Washington, Oregon and other parts of the country with lots of hills and mountains. Several states have developed rainfall thresholds to warn residents to take shelter from potential landslides.

“If we can just tighten that up a little bit and warn people during a potential landslide event, it could save lives,” said Carrie Jennings, a field geologist and professor at the University of Minnesota. “It’s more than just waiting to hear the noise in the middle of the night.”