The sound of a vehicle backfiring spooked a circus elephant while she was getting a pre-show bath in Butte, Montana, leading her to break through a fence and take a brief walk, stopping noontime traffic on the city's busiest street before being loaded back into a trailer.

Viola, an Asian elephant with the Jordan World Circus, still participated in two performances after her time on the lam in the southwestern Montana city of about 35,000 people that in the late 1800s was the world's largest copper producing area.

Viola was getting a bath behind the Butte Civic Centre when she was startled, Civic Centre manager Bill Melvin said.

She went through a “kind of rickety” fence and got out onto Harrison Avenue, a four-lane street, stopping traffic and causing folks to pull out their cellphones to take video.

Viola walked about half a block in the road before turning into the parking lot of a convenience store and casino, Melvin said.

An escapee elephant crosses the road in Butte, Montana. – AP

Town Pump surveillance cameras caught images from several angles of the elephant walking down the street in front of the building and plodding through the parking lot with a trainer beside her.

She then moved to a residential lawn where she started eating some grass.

People with the circus drove a trailer over with another elephant inside, Melvin said. They "put the ramp down and she walked right back in and that was it”.

It was about 10 minutes from when she was startled to when she was back in the trailer, he said.