LONDON — Met Office forecasters say Britain may face the coldest night of the year on Thursday and say snow predicted for parts of northern England may spread to a wider area.

The cold snap has snarled road traffic and led to some flight cancellations.

Officials at Stansted Airport said Thursday that normal flight operations had resumed but some of the 300 passengers who had been stranded overnight are still at the terminal. They are rebooking on other flights.

Flights had been suspended when the runway was closed due to ice. Luton Airport also reported some delays.

Several major highways are closed because of crashes and three climbers had to be rescued from the Cairngorms mountains in northeast Scotland.