Delta plane crash latest: 'Extreme conditions' at Toronto airport in ...

As investigators work to determine what caused Delta Flight 4819 to crash and overturn at Toronto Pearson International Airport on Monday, the Toronto Pearson president and CEO noted the "extreme conditions" at the airport in the days before the dramatic incident.

Toronto Pearson President and CEO Deborah Flint said that from Thursday to Sunday there were "extreme conditions" at the airport from two separate storms.

"On Thursday and Sunday, we got more than 20 inches, 50 centimeters of accumulated snow. That is actually not typical. In fact, it is more snow within that time window than we received in all of last winter," Flint said at a news conference Tuesday. "There were many delays and cancelations across this part of Canada and the U.S. Northeast during this time, creating numerous flight delays and backlogs."

"Monday was a clear day, though, and it was an operational recovery day for Toronto Pearson," Flint said.

The plane, which departed from Minneapolis, crashed amid blowing snow and strong wind gusts in the Toronto area. Winds reached 40 mph on the ground and were even stronger several hundred feet in the air.

When asked if the weather could have contribute to the crash, Flint said, "This would not be a time for us to have theory or to speculate."

Toronto Airport Fire Chief Todd Aitken said Monday that the runway was dry and there were no crosswind conditions at the time of the crash. When asked Tuesday if the runway had light snow or slush, he deferred the question to investigators.

The Transportation Safety Board of Canada is leading the investigation and investigators from the Federal Aviation Administration and National Transportation Safety Board are assisting. Investigators are expected to review the aircraft at its current position on the runway for the next two days, officials said Tuesday.

The Delta regional jet -- a CRJ 900 aircraft operated by Endeavor Air -- touched down, set fire, flipped over and came to a stop upside-down. The 76 passengers and four crew evacuated.

Flint on Tuesday praised the flight crew, saying they "heroically led passengers to safety."

She said she was grateful there was no loss of life or life-threatening injuries.

"I cannot commend enough the crew, the flight attendants, pilots and our emergency responders for their quick and effective response," Flint said. "It's really, really incredible, and when you see that aircraft, it just makes me really thankful."

Twenty-one passengers were taken to hospitals, and as of Tuesday, 19 of them have been released, according to Delta.

Injuries range from minor to critical, but non are life threatening, Flint said.

Injuries included "back sprains, head injuries, anxiety, some headaches, nausea and vomiting due to the fuel exposure," said Cory Tkatch, commander of operations at Peel Regional Paramedic Services.

Three people suffered critical injuries: one child, a man in his 60s and a woman in her 40s, according to medical transport organization Ornge.

There were 22 Canadian citizens among the passengers, Flint said.

The Toronto Airport temporarily stopped flights in the wake of the crash, with departures and arrivals resuming at 5 p.m. ET Monday, the airport said. Two runways remained closed, which Flint said may impact operations.

"Our most pressing priority remains taking care of all customers and Endeavor crew members who were involved," Delta CEO Ed Bastian said. "We'll do everything we can to support them and their families in the days ahead, and I know the hearts, thoughts and prayers of the entire Delta community are with them. We are grateful for all the first responders and medical teams who have been caring for them."