More than 2000 flights cancelled in US

Ahead of Christmas holidays, more than 2,270 US flights were cancelled on Thursday (local time) due to heavy snow and freezing temperatures, reported CNN.

Snow, rain, ice, wind and frigid temperatures are disrupting air travel plans across the United States and bus and Amtrak passenger train service.

Airlines cancelled just over 2,270 US flights by 6 ET pm Thursday and proactively cancelled almost 1,000 flights for Friday, according to the flight tracking site FlightAware.

Eighty-five flights were already cancelled for Saturday. Delays were even more extensive on Thursday: More than 7,400 as of 6 pm, reported CNN.

The impacts are being felt hardest in Chicago and Denver, where around a quarter of arrivals and departures -- hundreds of flights at each airport -- were cancelled on Thursday, FlightAware data show.

At one point on Thursday, at Chicago's O'Hare International Airport, delays averaging 159 minutes -- almost three hours -- were being caused by snow and ice, according to a notice from the Federal Aviation Administration.

Temperatures at the O'Hare dropped to 9 degrees Fahrenheit (-13 Celsius) around 5 p.m. local time. The National Weather Service reported snow and freezing fog.

The FAA said departing aircraft at Dallas Love, Dallas-Fort Worth, Denver and Minneapolis airports require spraying of de-icing fluid for safe travel, reported CNN.

Meanwhile, many airlines have issued weather waivers allowing travellers to change their itineraries without penalty during a short window.

For those whose flights are still scheduled to depart, the Transportation Security Administration is recommending that passengers arrive at the airport earlier than usual, reported CNN.

It's not just flights that are being affected by the bomb cyclone. Greyhound issued a service alert on Thursday warning customers that those travelling in the Midwest over the next two days may have their trips delayed or cancelled altogether.

Greyhound, the largest provider of intercity bus service, listed more than a dozen cities from West Virginia to Minnesota that are among those impacted, reported CNN.

Amtrak has also been forced to delay or cancel passenger service for some lines in the Midwest and Northeast.

In its notice, Amtrak said "customers with reservations on trains that are being modified will typically be accommodated on trains with similar departure times or another day", reported CNN.

"Amtrak will waive additional charges for customers looking to change their reservation during the modified schedule by calling our reservation centre at 1-800-USA-RAIL," it reported further.