Passengers stranded by flooding in Toronto were sprawled out in cots inside the Ottawa International Airport as they waited for a backlog to clear.

Airport officials said they brought out cots for about 300 passengers headed to Toronto from Hong Kong on Monday night after all available hotel rooms were booked.

They said it's the second time they've ever had to bring out cots to help diverted passengers.

Some passengers said they had a rough sleep but were grateful for the cots, blankets and Tim Horton’s vouchers after two days of travel.

The CBC’s Ryan Gibson said a flight is scheduled around noon to take them to Toronto. Others didn't wait, though, taking a bus or renting a car to get to their final destination.

In all, there were 20 flights diverted to Ottawa, including three major international flights. That closed one runway at the Ottawa airport to allow airplanes to park.

126 mm of rain more than Hurricane Hazel

As many as 300,000 customers lost power after torrential downpours caused flash floods in the Greater Toronto Area Monday evening.

Around 1,000 passengers were trapped inside a northbound GO Train, with emergency crews taking almost seven hours to rescue them all on inflatable boats.

About 126 millimetres of rain was recorded in some areas, an "unprecedented" amount that surpassed the one-day total from Hurricane Hazel in 1954, according to CBC meteorologist Jay Scotland.

Karen Stinz, chairwoman of the Toronto Transit Commission, said commuters should treat Tuesday like a "summer snow day."