Officials at Toronto's Pearson International Airport are warning it won't be a normal travel day today due to fallout from yesterday's extensive delays and cancellations caused by freezing temperatures.


Thousands of people are still trying to re-book flights after the airport came to a near standstill yesterday morning, when freezing temperatures caused widespread delays for arriving passengers.


Thousands of passengers arriving Tuesday morning waited hours for their planes to reach the gate, then hours more to claim their luggage. Some left the airport without their bags while unclaimed luggage covered the floor in some arrival areas.


The problem caused airport officials to issue a ground stop order early Tuesday. The order prevents new flights from arriving. The ground stop was lifted just after 10 a.m.


Airport officials blame Tuesday's shutdown on a domino effect of severe weather in the United States and Canada.


Plus double-digit below-zero temperatures led to frozen equipment and staff claiming it was just too cold to work outside.


The airport authority issued a message on Twitter just after 5:30 a.m. Wednesday, warning passengers there could be a "slow start up" on Wednesday.


As of 6 a.m. ET Wednesday, the GTAA website reported that 400 flights operating out of Pearson had been cancelled. About 20 per cent of scheduled departures had also been cancelled.