There is no sign of an end to the cold snap that is causing chaos across most of Europe.Italy faces a third day of heavy snow falls from the port town of Genoa to Milan. Hundreds of flights have been grounded at Milan’s airport but authorities hope some carriers will be able to take off this morning. Elsewhere, many roads are only open to cars using snow chains while heavy good lorries have been barred from routes leading to Switzerland. Many airports have either been closed or are running very limited services. Across southern France, at least 18 local authorities have declared extreme weather alerts. Authorities in several affected countries have warned people not to travel unless they have to with weather experts predicting the extreme cold spell will last for a few days.