At least 2,200 flights got cancelled across the United States as a major winter storm swept through the country, with the National Weather Service (NWS) calling it a “once-in-a-generation type event.”

The chill is expected to stay for the Christmas weekend, making this the coldest Christmas in about 40 years, say forecasters.

Those hoping to spend the Christmas holidays with their loved ones were left disappointed after the airlines cancelled more than 2,200 US flights by 1 pm ET on Thursday, and proactively cancelled more than 900 flights on Friday, according to the flight tracking site FlightAware.