A mix of snow and ice bore down on the US Northeast early on Saturday, disrupting post-holiday weekend airline traffic and prompting officials in New York and New Jersey to issue weather emergency declarations even as the storm ebbed by mid-morning.

People in much of the Northeast were advised to stay off the roads because of treacherous conditions, with states of emergency declared in New York and New Jersey.

“The safety of New Yorkers is my top priority, and I continue to urge extreme caution throughout the duration of this storm,” New York Governor Kathy Hochul said in a statement.

By early Saturday, about six to 10 inches (15 to 25 centimetres) of snow had fallen across an area from Syracuse in central New York to Long Island in the southeast of the state, as well as Connecticut, said Bob Oravec, a meteorologist with the National Weather Service’s Weather Prediction Centre near Washington, D.C.

New York City received two to four inches of snow overnight, with 4.3 inches reported at Central Park, Oravec said, the most since 2022.

“The good news is that the heaviest snow is done,” he said. “Only a few flurries remain this morning and those will taper off by the afternoon.”

But the effects were felt by travellers. More than 9,000 domestic US flights on Saturday were cancelled or delayed as of early-evening, with many in the New York area, including at John F. Kennedy International Airport, LaGuardia Airport and Newark Liberty International Airport, according to the tracking site FlightAware.

Representatives from American Airlines, United Airlines and JetBlue Airways told Reuters that the carriers had waived change fees normally charged to rebook for passengers whose travel plans may be affected by weather-related disruptions.

Ice storm warnings and winter weather advisories were also posted for most of Pennsylvania and much of Massachusetts.

New Jersey and Pennsylvania issued commercial vehicle restrictions for some roads, including many interstate highways.

“This storm will cause dangerous road conditions and impact holiday travel,” New Jersey’s acting governor Tahesha Way said in a statement. “We are urging travellers to avoid travel during the storm and allow crews to tend to roads.”