Photo courtesy: Robert Stephens
Photo courtesy: Becky Taylor
MINNEAPOLIS -- When a 24-inch underground natural gas pipeline exploded in south Minneapolis Thursday morning, it created huge traffic tie-ups and raised concerns about possible damage to a brand new bridge in the rebuilt Crosstown/Interstate 35-W interchange.
The Minnesota State Patrol eventually shut down traffic in both directions on 35-W for more than an hour, because the pillar of flame was creating both intense heat and a dangerous distraction for motorists.
"It was a huge challenge to get all that traffic redirected in that area," Kevin Walker of MnDOT told KARE, "But I think for the safety of the people out there, they understood that absolutely."
Walker said the distraction created by a column of flames rising 80 feet in the air, far above buildings and tree tops, was most likely a contributing factor in a dozen accidents in that part of the freeway system between 8:00 a.m. and 9:30 a.m.
"People were getting distracted, especially in the southbound lanes, as they tried to look back at the flames to see if they were really seeing what they thought they were seeing."
Once traffic stopped, MnDOT sent crews to inspect the bridges that cross East. 60th Street. From some vantage points it appeared the bridge was enveloped in flames, but in reality was nearly a block from the epicenter of the blast.
The intense heat, which partially melted cars in the nearby Cub Foods parking lot, was still conceivably hot enough to cause damage to the concrete and steel bridge.
Inspectors checked for signs of cracking, blistering and spalling in the concrete. Spalling is the term structural engineers use for concrete flaking away from the main body. Those crews found no signs of structural damage to the bridge or the sound walls nearby.
What appeared in aerial views to be "scorch" marks on the top of the bridge were actually stains from a slurry of leaves and mud blown out of the storm sewers by the power of the blast.
"It was a mixture of winter mush, that came up and splattered on the bridge," Walker said, "The mud came out of the ground and out of the manhole covers."
Firefighters evacuated residents from a six-block area, which included the Cub Foods store, several apartment complexes, a church with a daycare, and the students at Windom Spanish Dual Immersion School at 58th Street and Wentworth Avenue South, a few blocks away from the ruptured pipeline.
They spent the day at nearby Kenny Elementary. The Minneapolis district placed Kenny, Anthony Middle School and Armatage Montessori School on "code yellow lockdown" for the day, meaning children had to remain in classrooms with the doors shut.
"From the bedroom window it looked like a giant plume of fire rising up, sort of like a second sun," nearby resident A.J. Lee told KARE.
As he drove toward 35-W on 60th street, it appeared the flames were licking the interstate bridge.
"For a second you stop and think, is the sky just turning into fire?" Lee exclaimed, "The rushing sound just kept going, and it was like one giant propane torch!"
Kate Darkstar, who lives on 2nd Avenue South, across the street from the 35-W bridges, was among those roused from her sleep by the ruckus. In her mind a knock on the door came before the blast.
"That's what woke me up," Darkstar said, "It was the pounding on my door, and then just about when I opened up my door, I heard a big huge 'kaboom'!"
She couldn't find the person who had knocked on her door, but she looked at the bridge and was stunned.
"I saw the fire bomb, and the bridge underpass was filled with smoke. You couldn't even see through it," she said, "And then it started raining mud drops on my house and car."
"The firemen were all running around to houses telling everybody, 'Evacuate now! Evacuate now'!"
Still dressed in a robe Darkstar grabbed her dog Lucy and made her way to Pearl Park, six blocks to the north. Even from that distance she could see the flames rising far above the trees. When the flames subsided she drove closer to her home.
After fire crews and technicians from CenterPoint Energy checked Darkstar's home for stray gas she was allowed to return. At that point she realized the blast had knocked her ornate angel doorbell off the front wall of her home.
Incredibly, no injuries
The exact cause of the blast remained unknown Thursday evening. Witnesses and those who responded to the scene continued to remark throughout the day that it was miraculous nobody was injured or killed in the blast and fire.
The grocery store surveillance tape showed several cars driving westbound on 60th street, passing over the precise spot of the blast, just seconds before the street erupted in mud and fire.
On a busy weekend day, the parking lot would've been filled with customers including small children. But on a slow Thursday morning and school day, customers were outnumbered by employees.
A huge crater marked the spot of the blast Thursday night, as crews worked to secure the scene. The Cub Foods reopened for business at 3 p.m., but customers had to share the parking lot with street crews and teams from CenterPoint.
Many returned to the parking lot to find their vehicles partially melted by the temporary blast furnace that raged for nearly 90 minutes. The plastic in the store' large signs also shriveled in the heat.
(Copyright 2011 by KARE. All Rights Reserved.)