Heavy rain Wednesday triggered multiple rock- and mudslides that forced the Minnesota Department of Transportation to close the southbound lanes of Hwy. 169 between St. Peter and Mankato.

One northbound lane of Hwy. 169 was also closed as debris spilled across the median, said MnDOT spokeswoman Rebecca Arndt.

“This one is a doozy,” she said. While crews responded to the first slide, “then there was another and then another.”

Motorists were advised to use alternate routes, such as Hwy. 22, as the road remained blocked with mud, rocks and trees just south of St. Peter, Arndt said. The southbound lanes of Hwy. 169 were to remain closed overnight.

Northbound 169 in that area was expected to remain open, but drivers are being told to be cautious.

Heavy rains, as much as 2 inches in an hour, left standing water on Hwy. 169 and ditches filled up with water from the runoff, Arndt said.

A mudslide on Hwy. 169 near St. Peter, Minn., closed the highway.

“Motorists need to use caution,” she added.

Rains also have led to flooded roads in St. Peter, and urban flooding may be possible in other places as thunderstorms rolled across southern Minnesota, the National Weather Service said.