The north-eastern US states of New York, New Jersey, Pennsylvania and Virginia have declared states of emergency as a huge winter storm sweeps in, bringing heavy snow. The US National Weather Service issued blizzard warnings from eastern Pennsylvania to south-west Maine. Schools are closed and thousands of flights have been cancelled. There has also been heavy snow in other parts of the country. In the state of Wisconsin, four people aged over 60 died in separate incidents while shovelling snow.