Thousands of flights in the US were cancelled or delayed due to a severe winter storm hitting the northeast during the busy holiday season. By Friday night, 1,600 flights were cancelled and 7,400 delayed, according to FlightAware. The hardest-hit airports are John F Kennedy International, Newark Liberty, and LaGuardia, all serving New York. Boston, Chicago, and Toronto also face disruptions. The National Weather Service issued a winter storm warning from 16:00 Friday to 13:00 Saturday, predicting up to 9 inches (23 cm) of snow in New York and southern Connecticut. JetBlue cancelled 229 flights, Delta 241, Republic Airways 180, Southwest Airlines 151, and American and United Airlines about 100 each. Airports warned travelers on social media to check flight statuses. The heaviest snow was expected between 18:00 and midnight. Drivers were warned of dangerous road conditions and advised to carry emergency supplies. New York Governor Kathy Hochul said, "People should avoid unnecessary trips, but if they had to travel, they should 'plan ahead, take it slow, and leave plenty of time to get to where you need to go safely.'" Similar warnings came from New Jersey and Connecticut governors. This storm is the second major snowfall for New York this season after several inches fell on December 14. Mayor Eric Adams urged commuters who drove to work to leave early or use public transport home. Snow ploughs are on standby to clear streets once two inches of snow fall.