Transportation workers have reopened a stretch of Hwy. 13 in Lilydale, hours after a mudslide blamed on a lawn-irrigation system shut it down in both directions.

The Minnesota Department of Transportation reopened the highway between Wachtler Avenue and Sylvandale Road around noon Thursday. Throughout the morning, workers stood at either end of the closure in the hazy heat, directing motorists away from the site as others cleared mud from the roadway and made sure power lines were stable.

Down the street, longtime homeowner Dan Caruso said mudslides and road closures in the area have become more frequent in recent years.

“It happens,” he said. “You just hope no one is around when it happens.”

The mudslide on Thursday started on private property at the top of the bluff, on a quiet residential street in Mendota Heights. Public Works Director Ryan Ruzek said a faulty irrigation system flooded a backyard and eventually caused a retaining wall to fail.

Water is often a contributing factor when bluffs collapse, said Tony Runkel, chief geologist at the Minnesota Geological Survey.

“The more moisture that you get infiltrating into the ground, the heavier everything becomes,” he said. “You’re filling up what was airspace with water.”

In 2014, MnDOT closed Hwy. 13 between 2nd Street and Lexington Avenue in Mendota Heights after heavy rains caused a small mudslide and made a slope above the highway unstable. The road was closed for two weeks while MnDOT worked to stabilize the area.