Survivors of the Delta flight that crash-landed in Toronto and flipped over recounted "hanging upside down like bats" in the aftermath of the crash and having no warning ahead of it, ABC News reported Tuesday.

All but two of the 21 passengers who were injured have been released from area hospitals, airline officials said Tuesday, one day after Delta Flight 4819 carrying 80 passengers and crew flipped upon landing at Toronto's Pearson International Airport. Nine inches of snow fell on the airport on Sunday.

"How grateful we are there was no loss of life or life-threatening injuries," Deborah Flint, CEO of Greater Toronto Airports Authority, said Tuesday during a news conference. "The crew heroically led passengers to safety."

Passenger John Nelson told ABC News on Tuesday that "there was no warning" and described hitting the runway "extremely hard."

"It was just incredibly fast. There was a giant firewall down the side. I could actually feel the heat through the glass," Nelson told ABC News. "Then we were going sideways. I'm not even sure how many times we tumbled, but we ended upside down."

Passenger Peter Koukov told ABC News, "We hit the ground, and we were sideways and then we were hanging upside down like bats."

"It all happened pretty, pretty fast. The plane was upside down, obviously, some people were kind of hanging and needed some help being helped down," Koukov added.

"We released the seat belts. I kind of fell to the floor, which is now the ceiling, and helped the lady next to me get out of her seat belt," Nelson told ABC News.

The Delta regional jet operated by Endeavor Air arrived from Minneapolis on Monday afternoon. At the time of landing, winds were gusting up to 40 mph, according to ABC News.

Investigators will consider the weather conditions, as well as the possibility of human error or an aircraft malfunction as they try to determine why the jet burst into flames and flipped upside down as it tried to land, aviation experts said Tuesday.

"This is an active investigation. It's very early on," Todd Aitken, fire chief at Toronto Pearson International Airport, told reporters Monday. "It's really important that we do not speculate. What we can say is the runway was dry and there were no crosswind conditions."

The Transportation Safety Board of Canada is leading the investigation with support from the U.S. National Transportation Safety Board.

Information from The Associated Press was used in this report.

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