Snow blown by winds gusting to 40 mph (65 kph) swirled when the flight from Minneapolis carrying 76 passengers and four crew attempted to land at around 2:15 p.m. Communications between the tower and pilot were normal on approach and it’s not clear what went so drastically wrong when the plane touched down.

Peter Carlson, a passenger traveling to Toronto for a paramedics conference, said the landing was “very forceful.”

“All the sudden everything just kind of went sideways and then next thing I know it’s kind of a blink and I’m upside down still strapped in,” he told CBC News.

Canadian authorities held two brief news conferences but provided no details on the crash. Video posted to social media showed the aftermath with the Mitsubishi CRJ-900LR overturned, the fuselage seemingly intact and firefighters dousing what was left of the fire as passengers climbed out and walked across the tarmac.

“We are very grateful there was no loss of life and relatively minor injuries,” Deborah Flint, CEO of Greater Toronto Airports Authority, told reporters.

Delta CEO Ed Bastian said in a statement that “the hearts of the entire global Delta family are with those affected.”

Toronto Pearson Fire Chief Todd Aitken said 18 passengers were taken to the hospital. Earlier in the day, Ornge air ambulance said it was transporting one pediatric patient to Toronto’s SickKids hospital and two injured adults to other hospitals in the city.

Emergency personnel reached the plane within a few minutes and Aitken said the response “went as planned.” He said “the runway was dry and there was no cross-wind conditions.”

The crash was the fourth major aviation accident in North America in the past three weeks. A commercial jetliner and an Army helicopter collided near Reagan National Airport in Washington, D.C., on Jan. 29, killing 67 people. A medical transportation plane crashed in Philadelphia on Jan. 31, killing the six people on board and another person on the ground. And on Feb. 6, 10 people were killed in a plane crash in Alaska.

The last major crash at Pearson was on Aug. 2, 2005, when an Airbus A340 landing from Paris skidded off the runway and burst into flames amid stormy weather. All 309 passengers and crew aboard Air France Flight 358 survived the crash.

On Monday, Pearson was experiencing blowing snow and winds of 32 mph (51 kph) gusting to 40 mph (65 kph), according to the Meteorological Service of Canada. The temperature was about 16.5 degrees Fahrenheit (minus 8.6 degrees Celsius).

The Delta flight was cleared to land at about 2:10 p.m. Audio recordings show the control tower warned the pilots of a possible air flow “bump” on the approach.

“It sounds to me like a controller trying to be helpful, meaning the wind is going to give you a bumpy ride coming down, that you’re going to be up and down through the glide path,” said John Cox, CEO of aviation safety consulting firm Safety Operating Systems in St. Petersburg, Florida.

“So it was windy. But the airplanes are designed and certified to handle that,” Cox said. “The pilots are trained and experienced to handle that.”

The plane came to a rest at the intersection of Runways 23 and 15L, not far from the start of the runway. Just after the crash, tower controllers spoke with the crew of a medical helicopter that had just left Pearson and was returning to help.

“Just so you’re aware, there’s people outside walking around the aircraft there,” a controller said.

“Yeah, we’ve got it. The aircraft is upside down and burning,” the medical helicopter pilot responded.

Carlson was among those outside the aircraft. He said when he took off his seat belt he crashed onto the ceiling, which had become the floor. He smelled gas, saw aviation fuel cascading down the cabin windows and knew he needed to get out but said his fatherly intuition and paramedic skills kicked in. He looked for those he could help.

Carlson and another man assisted a mother and her young son out of the plane and then Carlson dropped onto the tarmac. Snow was blowing and it “felt like I was stepping onto tundra.”

“I didn’t care how cold it was, didn’t care how far I had to walk, how long I had to stand — all of us just wanted to be out of the aircraft,” he said.

Cox, who flew for U.S. Air for 25 years and has worked on U.S. National Transportation Safety Board investigations, said the CRJ-900 aircraft is a proven aircraft that’s been in service for decades and does a good job of handling inclement weather.

He said it’s unusual for a plane to end up on its roof.

“We’ve seen a couple of cases of takeoffs where airplanes have ended up inverted, but it’s pretty rare,” Cox said.

Among the questions that need to be answered, Cox said, is why the crashed plane was missing its right wing.

“If one wing is missing, it’s going to have a tendency to roll over,” he said. “Those are going to be central questions as to what happened to the wing and the flight data recorder and cockpit voice recorder. They will be found, if not today, tomorrow, and the Transportation Safety Board of Canada will read them out and they will have a very good understanding of what actually occurred here.”

The U.S. Federal Aviation Administration said in a statement that the Transportation Safety Board of Canada would head up the investigation and provide any updates. The NTSB in the U.S. said it was sending a team to assist in the Canadian investigation.

Endeavor Air, based in Minneapolis, is a subsidiary of Delta Air Lines and the world’s largest operator of CRJ-900 aircraft. The airline operates 130 regional jets on 700 daily flights to over 126 cities in the U.S., Canada and the Caribbean, according to the company’s website.

The CRJ-900, a popular regional jet, was developed by Canadian aerospace company Bombardier. It’s in the same family of aircraft as the CRJ-700, the type of plane involved in the midair collision near Reagan National Airport on Jan. 29.