While the situation left hundreds of people trapped in their cars in freezing conditions, by the early hours of Wednesday morning, traffic was moving again, according to police.

“The difficult situation began yesterday after 4 pm, when the first trucks on the S7 route… began having trouble approaching the slopes,” said Tomasz Markowski, a spokesperson for police in the northern city of Olsztyn.

“This led to a traffic jam stretching approximately 20 kilometres overnight.”

Deputy Infrastructure Minister Stanislaw Bukowiec told a press conference that nobody had been hurt as a result of the difficult situation on the roads.

Anna Karczewska, a spokesperson for police in Ostroda, said officers had tried to help drivers who found themselves stuck. Ostroda lies on the highway about 40 km west of Olsztyn.

“We helped as much as we could, and we had coffee and hot tea for the drivers, which the Ostroda City Hall had prepared for us,” she said.

State news agency PAP reported that there had also been some disruption to railways and airports, but that services were returning to normal.