Heavy snow and sub-zero temperatures have swept across Europe killing at least eight homeless people, closing major airports and causing hundreds of road accidents.
Geneva, a major hub for low-cost carrier Easyjet, was forced to shut as staff struggled to clear runways of snow. Chambery and Grenoble airports in south-eastern France were also closed.
Eurocontrol, the central air control agency, reported severe flight delays in Frankfurt, Munich, Vienna and Prague.
In Poland, police said eight homeless men died on Tuesday night after a bitter cold front roared in, with temperatures falling to around -20C. Police said the men, from different parts of the country, had been drinking. The eastern Polish city of Bialystok hit -26C.
Winter weather caused some 2,000 accidents on German roads on Tuesday, officials said.
Police in northern Austria said a 69-year-old man froze to death overnight when he slipped on a snow-covered bridge on his way home from a funeral and lost consciousness.
Zurich, Switzerland's biggest airport, reported delays and cancellations on the day many VIPs, including former President Bill Clinton and Spanish Prime Minister Jose Luis Rodriguez Zapatero, were travelling to Fifa's headquarters to push their countries' bids to host the 2018 and 2022 football World Cups.
An airport spokeswoman said officials anticipated heavy snowfall but expected to keep flights going. However the presence of so many private jets in Zurich meant the airport had to turn down requests for diverted landings.
Around 60 flights were cancelled at Frankfurt airport, Germany's largest, since planes were not able to fly in on Tuesday, but there were no weather delays on Wednesday.
Swiss weather agency Meteosuisse forecast more snow as a low-pressure front centred over western Europe moved slowly eastward.