Transportation Safety Board officials are investigating what caused a WestJet Boeing 737 from Toronto to skid off the runway while landing at Montreal's Trudeau airport Friday afternoon.

WestJet officials said via Twitter that no one was injured on Flight 588, which was carrying 110 passengers.

Passenger Greg Brown told CBC News that "near the end of the landing, all of a sudden you could feel the plane — we hit like a fog patch. We couldn't see anything out the window and I'm guessing he couldn't see anything. 

"He claimed that we hit standing water and the plane veered off to the right. It's strange to be turning when you're landing, you know?  We came to a stop, looked out the window and we were in the grass."

An eyewitness on another plane that landed at about 2:45 p.m. watched as the WestJet plane skidded off the runway.

"We were taxiing out to disembark, and the wife and I were looking out the window, and we saw a WestJet flight landing, and he just wasn't stopping, and kind of skidded right off the tarmac into the grass," Joe Macri told CBC News.

"And it was very, very odd, and we looked over and said, 'Did that really just happen?'"

It was raining heavily at the time of the incident. Officials would not say whether that played a factor in the plane skidding off the runway.

Stéphanie Lepage, a spokeswoman for Montreal Pierre Elliot Trudeau Airport said such an incident is very rare — something she has only witnessed two or three times throughout her career.

The aircraft had no signs of visible damage.

Shortly after 4 p.m., all passengers and crew were off the plane.

Firefighters and emergency crews were on hand to help passengers disembark.

The Transportation Safety Board is investigating the incident.

Long delays

The investigation on the ground at Trudeau airport caused long delays for some Montreal-bound travellers whose flights landed Friday evening.

CBC reporter Leah Hendry was on a flight that landed in Montreal two hours late, and after landing the plane was parked on the tarmac for an hour.

"The captain told us a couple of times that it's an utter mess at the airport, that the crews are trying to load and unload planes that should have already been gone, and there is no crew to get us off the plane — a cascade effect from what happened earlier today," Hendry said.

By 11:30 p.m. Friday, about a dozen flights that were scheduled to be either departing or arriving in Montreal were expected to be delayed.