Up to 50 million people may be affected by dangerous conditions building up Saturday in Canada and northeast United States. Up to 3 feet of snow and 75 mph gales threaten New York, New England, New Hampshire and Massachusetts, whose governors have declared an emergency. Massive power cuts leave hundreds of thousands of people without electricity. Airlines and trains have suspended operations in New York and New England and people urged to stay off dangerous roads in the worst hit areas. Flights bound for the United States from Israel are awaiting better weather before taking off. Ticket holders are advised to check in with the airlines for departure times.