Airlines including Air Canada and WestJet have updated their travel alerts ahead of this weekend’s major winter storm.

As reported yesterday, Air Canada’s winter operations travel alert is in effect for a number of U.S. cities, allowing passengers travelling to and from those cities on the listed dates to change their flights free of charge.

Air Canada has now added another day of travel alerts, and more cities.

Here’s Air Canada’s latest list …

Jan. 23 – Dallas (DFW) and Houston (IAH)

Jan. 24 – Dallas (DFW), Houston (IAH), Nashville (BNA) and Raleigh Durham (RDU)

Jan. 25 – Boston (BOS), Cleveland (CLE), Houston (IAH), New York (EWR), New York (JFK), New York (LGA), Philadelphia (PHL), Pittsburgh (PIT), Raleigh Durham (RDU), Washington (DCA) and Washington (IAD)

Jan. 26 – Boston (BOS), Cleveland (CLE), Dallas (DFW), Houston (IAH), Nashville (BNA), New York (EWR), New York (JFK), New York (LGA), Philadelphia (PHL), Pittsburgh (PIT), Raleigh Durham (RDU), Washington (DCA) and Washington (IAD)

Jan. 27 – Boston (BOS), Raleigh Durham (RDU), Washington (DCA) and Washington (IAD)

More information for Air Canada passengers can be found here.

WestJet is also offering its flexible rebooking policy, currently for travel on or between Jan. 24 – 25, to / from Atlanta, GA and Houston, TX (G. Bush Intercontinental), and also just added, for travel on or between Jan. 25 – 26, to / from New York (JFK).

More information for WestJet passengers can be found here.

Massive Storm System

More than 800 flights within, into, or out of the U.S. were delayed or cancelled for the day in advance of a major winter storm, including at airports in Dallas, Atlanta, and Oklahoma, according to the flight tracking website FlightAware.

Forecasters predict a huge, days-long winter storm threatening catastrophic damage, extensive power outages and bitterly cold weather to the eastern two-thirds of the U.S.

The massive storm system is expected to bring a crippling ice storm from Texas through parts of the South, potentially around a foot (30 centimetres) of snow from Oklahoma through Washington, D.C., New York and Boston, and then a final punch of bitterly cold air that could drop wind chills to minus 46 degrees Celsius in parts of Minnesota and North Dakota.

Forecasters are warning the damage, especially in areas pounded by ice, could rival a hurricane. About 160 million people were under winter storm or cold weather watches or warnings — and in many places both.

Freezing temperatures are expected all the way to Florida, forecasters said. Winter storms can be notoriously tricky to forecast, with forecasters saying the places with the worst weather can’t be pinned down until the event starts.

With file from The Associated Press