A fast moving and violent storm struck northern and central Alberta Thursday, shutting down the main highway between Calgary and Edmonton and causing pileups that left more than 100 people injured.

CBC confirms that four of those who needed medical attention were in serious condition.

The pileups occurred between along the QEII Highway between Wetaskiwin and Edmonton, with the biggest one taking place near Leduc, just south of the capital.

Alberta Health Services told Metro they have never dealt with anything like this but that they do have plans in place to deal with such situations and are treating the incident as a mass casualty event.

Alberta Health Services reported approximately 100 patients needed medical attention resulting from crashes along the heavily-traveled highway.

According to CBC Edmonton, injured people are being transported to hospitals around the area, including Edmonton, Red Deer, Leduc, St. Albert, Fort Saskatchewan, Devon, Wetaskiwin, Stony Plain, Lamont and Camrose.

The pileups forced Mounties to shut down the QEII Highway at several locations late Thursday morning, diverting traffic to other thoroughfares, which resulted in massive lineups and slow moving traffic.

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  • More aftermath from yesterday's massive pileup on #QE2 during #snowmageddon

  • Stuck in a big crash on QEII Our Red Arrow is fine

  • Bunch of rookies. #justkidding #drivesafe

  • Another picture from pileup south of Leduc.

  • Still parked on QE2 Southbound. Just spoke with this guy who says he's walking to the airport (about 7k). pic.twitter.com/EvRCojK5L0

  • Near Leduc.

  • Edmonton roads are not safe today! 100 car pile-up.

  • Yikes, this is a photo a friend just sent me of the 100-car pileup in Edmonton. Stay safe everyone...

  • Another one hits the ditch.

  • See what we livin' in?

  • Here's a panorama of the view in front of the crash.

  • This is my back yard today .. 6 inches of snow expected.

  • Just did my #RAOK for today. Shovelled the block. Too bad it's still snowing.

  • At the team meeting and I see the largest icicle I've seen in a long time.

  • Springtime in Edmonton!

  • Our vehicles are learning how to blend in and #camouflage with their surroundings.

"The number of vehicles involved in the collision and the extent of any injuries is not unknown at this time," said Wetaskiwin RCMP Const. Karolina Malik.

It was the same situation further north as other collisions forced Mounties to block off the highway closer to Edmonton.

Social media reports said entire stretches of the highway were littered on either side with cars, semis and buses that had ended up on the ditch or along the centre of the thoroughfare.

"Several vehicles and a Tractor Trailer are off the road and in the ditch due to slippery road conditions," said Leduc RCMP spokesperson Const. Tim Gaultois, adding it will be sometime before the full extent of the carnage is known.

RCMP blamed blowing snow, icy conditions and low visibility for the countless pileups across central and northern Alberta.

"Police are also advising motorists that happen to go off the road or get stuck to stay in their vehicles until they can safely get alternative transportation and not to walk on or near the highway as it is unsafe to do so."

The storm also caused massive traffic delays within the capital city limits, declared the City of Edmonton, while Anthony Henday Drive - Edmonton's ring road and of the city's most trafficked thoroughfares - also had to be shut down to all traffic.

CORRECTION: A previous version of this story quoted AHS as saying the total number of people hurt in these pileups totaled 300. AHS has revised that figure. They now say the actual number is 100. We apologize for any confusion this may have caused.

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