Blinding snow squalls, high winds and a slick highway led to a series of crashes in Detroit Thursday that left at least three people dead, including two children from Windsor, Ont.

Michigan State Police Lt. Michael Shaw said visibility was extremely poor when the mass of crashes happened on Interstate 75 on the southwest side of Detroit.

"We had some reports from witnesses of whiteout conditions ... where a snow squall came across the freeway bringing the visibility down to practically zero," he said.

Shaw said the two children killed in the crash were a 7-year-old boy and his and 9-year-old sister, both from Windsor, Ont.

Their father suffered non-life-threatening injuries, while the mother was transported to hospital in critical condition.

The adult killed in the crash was from the United States.

SUVs with smashed front ends and cars with doors hanging open sat scattered across the debris-littered highway, some crunched against jackknifed tractor-trailers and tankers. Rescue crews went vehicle to vehicle in the search for survivors and to provide aid.

"We believe some of the crashes were caused by following too closely to the vehicle in front of them or driving too fast for road conditions," Shaw said, adding that at least 13 people had been taken to hospital, two in critical condition.

There were 'people bleeding, people limping, people shaken up.'—Phillip Bost, semi-truck driver involved in crash

Motorists and passengers who were able to climb out of their vehicles huddled together on the side of the road, some visibly distraught, others looking dazed. A man and woman hugged under the grey, cloud-filled skies, a pair of suitcases next to them and a bumper on the ground behind.

About 30 vehicles involved in pileup

Conditions went from "clear to total whiteout in a matter of seconds," Shaw said. "All of a sudden, they couldn't see anymore."

About 30 vehicles were involved in the pileups and many more were trapped on the freeway behind the accident scene for hours. Shaw said it could be hours before the freeway is fully reopened.

Greg Galuszka was driving a fuel truck along I-75 when white-out conditions quickly materialized.

"I looked on my driver's side mirror, and I could see the trucks piling up back there," Galuszka said, pointing to a mass of twisted metal where vehicles had smashed into each other a short time earlier.

"Then, when I looked in my passenger side [mirror], is when I saw the steel hauler coming up," he said. "I just said my prayers from there and said, 'Please don't hit me.'"

'I heard booms and bangs behind me'

Phillip Bost was driving a semi-truck loaded with auto parts when the snow squall hit. Bost said he rushed to help the injured when alerted by the terrifying sound of the crashes.

"I heard booms and bangs behind me. Boom, boom, boom, boom," said Bost of Ypsilanti, Mich.

There were "people bleeding, people limping, people shaken up. It was a bad ordeal," he recalled several hours later. "I'm quite shaken up."

Shaw said many people had to be pulled from their vehicles. Numerous fire engines and ambulances were at the scene.

The crash happened as snow and strong blustery winds reduced visibility across southeastern Michigan, said Bryan Tilley, a meteorologist with the National Weather Service in Oakland County's White Lake Township.

More than two dozen vehicles, including tractor trailers, were involved in a mile-long stretch of pileups. (Paul Sancya/Associated Press)

"There was a pattern of snow showers moving through the area in the midmorning hours," Tilley said. Nearby Detroit Metropolitan Airport had west winds at 30 kilometres per hour, with gusts to 50 kp/h around the time of the crash. The temperature of -4 C was about 20 degrees colder than a day before.

The crash happened near an elevated stretch of expressway where the road surface can cool quickly and make driving hazardous, Tilley said.

Lisa Czarnecki said she hurried to the crash scene from her office in downtown Detroit after her husband, Ken, called to say he had been involved in the crashes. Ken was driving at about 50 kilometres per hour when the vehicles in front of him suddenly stopped but he wasn't able to stop too, leaving "the front of his car under that white semi," she said, pointing to the highway.

"After I identified the car to one of the [emergency] workers, I asked them to go tap on the window and ask him to wave out the door," Lisa Czarnecki said. "They managed to get him out of the vehicle and he stood up and waved."

With files from CBC News