SAN DIEGO — Police are advising drivers to avoid an area in Pacific Beach where a BMW went out of control, hit a pedestrian, crashed into another car and flipped.

It happened around 1:17 p.m. Monday at the intersection of Garnet Avenue and Mission Bay Drive in Pacific Beach. A man was driving a silver BMW 4-door sedan northbound in the 4600 block of Mission Bay Drive when he drifted into the southbound lanes and hit a 64-year-old man who was standing in the center divide, police said. The BMW continued through the intersection of Mission Bay Drive and Garnet Avenue and hit a southbound white Ford Fusion sedan. The BMW flipped and landed on its roof, investigators said.

Gabe Orellana is the manager of Enterprise rental car, he saw the whole things happened, “I heard a loud bam and then saw the car airborne. It crashed through the fence.”

The pedestrian suffered life-threatening head injuries, a broken pelvis and internal injuries and was taken to a hospital for treatment. The 31-year-old woman driving the Fusion complained of pain. The 40-year-old driver of the BMW was not seriously injured. He was up and walking around.

A girl who works in the area helped him out of his car. She said he was bloodied and then went into Enterprise and cleaned up and then came back outside.

The cause of the crash was under investigation, but as of 5 p.m., no one had been arrested and the driver of the silver BMW left the scene on his own.

Police said Garnet would be shut down in both directions between Morena Boulevard and Bond Street, as well as the southbound lanes of Mission Bay Drive from Damon until at least 6 p.m. Monday. Northbound Mission Bay Drive was narrowed to one lane between Damon and Garnet. Officers were advising drivers to use alternate routes.