Cub Foods store director Randy Drescher was hanging signs near the store's front entrance at 60th Street and Nicollet Avenue in Minneapolis Thursday when his quiet morning literally exploded.

"All we saw was a big pile of dirt fly up into the air about 50 feet," he said. "And the flames came shortly after."

The blaze on 60th Street just north of Hwy. 62 was caused by a leak in an underground natural gas pipe that ignited, blowing a crater in the road and sending flames several stories into the air.

The Crosstown and Interstate 35W were closed for several hours, tangling rush hour traffic. Authorities asked residents of parts of south Minneapolis and Richfield to leave their homes as a precaution, sending a parade of people in pajamas and flip-flops into the streets.

"The firefighters were running down the street and banging on doors," said Mirah Ammal. "We took our four cats and ran out the door."

CenterPoint Energy spokesperson Becca Virden said the cause of the fire, which started shortly after 8 a.m. and burned until almost 10 a.m., had not been determined late Thursday afternoon. She said the company did not know if there had actually been an explosion in the 20-inch steel pipe, which dated from 1994.

"It's still under investigation," she said. "Our underground pipeline had a leak in it, and it got ignited somehow."

Virden said reports of blasts may have stemmed from manhole covers being blown off streets from heat and pressure. Two natural gas lines serve the area, so no one lost service, she said.

Fire and hissing gas

Robert Stephens, founder of the Geek Squad, was driving from a tire shop in the area when he saw what he first thought was a house on fire.

"I could feel the heat through the car windows six or seven blocks away," Stephens said. He drove down Nicollet Avenue past the blaze, shooting video on his iPhone through his open car window. He said flames shot at least 100 feet into the air, and he could hear escaping gas hissing as he drove by.

As he headed to work, fire trucks with blaring sirens passed. Barely 10 minutes later, Stephens' wife called him and said firefighters had already visited their home 10 blocks from the fire and asked her to evacuate.

"I am very impressed with the way this was handled," Stephens said.

Though the fire was more than 100 feet from the Cub Foods, the temperature was so searing at the front of the store that customers and employees were forced to run out the back exit. In the parking lot, tires melted and paint blistered on vehicles. Power lines and utility poles were damaged. Amazingly, no one was hurt.

Brad Solem, service leader at Bobby & Steve's at 5801 Nicollet Ave. S., was outside the back of his shop when he heard what he assumed was an explosion just a block or so away.

"Just a 'boom,' and then the flames instantly shot sky high," he said. "You could instantly feel heat on your face."

Firefighters and police knocked on doors in south Minneapolis and Richfield in an area bordered by Diamond Lake Road, Harriet and Portland Avenues and 66th Street. About 9,000 people live in the area's 4,500 housing units, including apartments. Evacuation was voluntary, but many people grabbed children and pets and hurried away from the area.

A hurried evacuation

Richard Ojar walked north on Nicollet in a T-shirt, shorts and flip-flops. "I didn't have time to get anything else," he said.

Bob and Marilyn Harris were eating breakfast in their home on 2nd Av. S., next to the freeway, when she spotted a "light like the sun" over the freeway noise wall. They assumed a car was on fire.

"We opened the door and it was very hot," she said. Shortly after, the pair --he's 80, she's 79 -- were asked to leave by a firefighter.

Robert Barth, 79, walked a block, aided by his cane, to get outside the evacuation zone after a warning from a firefighter. "She said [the gas] may come in through our sewers," Barth said.

The last thing he'd seen like the gas fire, he said, was the burning napalm he saw as a serviceman in Korea.

Some of the people who left their homes took refuge in a Metro Transit bus until they were allowed to return home around 11 a.m. The Cub Foods reopened in the afternoon.

Students at Windom School, the school closest to the fire, were moved west to Kenny School, Minneapolis school district officials said. Kenny and Armatage elementary schools and Susan B. Anthony Middle School were placed on lockdown, meaning students were required to remain in the building for the balance of the school day.

Northbound and southbound lanes of 35W reopened late Thursday morning, though the southbound ramp at 60th Street remained closed, MnDOT said. The bridge that goes from southbound 35W to Hwy 62 and spans 60th Street was inspected and determined to be safe. Nicollet Avenue between E. 59th and E. 61st Streets was expected to remain closed while the fire is investigated.

Star Tribune staff writers Steve Brandt, Patrick Doyle, Glenn Howatt, Mike Hughlett, Josephine Marcotty, Warren Wolfe, Corey Mitchell, James Walsh and Paul Walsh contributed to this report. Mary Jane Smetanka • 612-673-7380