A semitrailer truck carrying 25 tons of gravel rolled over and burst into flames Tuesday morning on westbound Hwy. 36 in Lake Elmo.

The truck landed on its side after flipping over about 10:30 a.m., blocking both westbound lanes at the intersection of Hwy. 36 and Manning Avenue, the Minnesota Department of Transportation said.

The truck caught fire and sent a plume of white smoke into the air, MnDOT traffic cameras showed.

Westbound traffic near the crash scene was being diverted through an opening in the median and turned back to the east. Other westbound traffic was being diverted off the highway at Stillwater Boulevard. Eastbound lanes were closed at Lake Elmo Avenue, MnDOT said.

A MnDOT spokesman in the agency’s traffic management center said he expected the highway to be closed for three to four hours while crews turned the burned truck upright and cleaned up the spilled gravel.

The State Patrol advised motorists to find an alternate route.

There was no immediate word about any injuries.