An Air Canada flight to Toronto from Shanghai, China was diverted to Calgary Wednesday after severe turbulence injured 21 passengers, including three children.

Emergency Medical Services spokesman Stuart Brideaux told reporters that the injured were transported to Calgary-area hospitals and were in stable condition with non-life threatening neck and back injuries.

Air Canada said eight of the passengers on board Flight 88 were being treated for injuries, while the others were being kept overnight for hospitalization.

CBC News reported that injured passengers were taken through the terminal in stretchers and wheelchairs to waiting ambulances. Fire and other emergency crews were on hand when the plane landed, including 15 ambulances. Air Canada said the aircraft landed  "without incident," shortly after 5 p.m. ET.

One passenger told CBC the turbulence began as the aircraft was flying over northwestern Canada. 

"I was laying flat in a business class seat, I had my seatbelt on and suddenly I saw the passenger in front of me go flying up in the air, literally to the ceiling, and then hitting the ground again," the passenger, known only as Zarum, told the network. "And then passengers started screaming and objects started flying. It last maybe half an hour."

“The girl beside me, she was thrown right out of her seat, down the aisle,” passenger Connie Gelber told CTV News. “We thought we were dying.” Gelber later described the turbulence as "unbearable."

"I heard lots of people screaming, like what you would hear on a roller-coaster," another passenger, Bing Feng told CBC. "You saw all the oxygen masks drop."

Canadian authorities said an investigation would be conducted that would include interviews with crew members and analysis of the digital flight recorder and the cockpit voice recorder.

The Associated Press contributed to this report.

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