New York, Boston to be blanketed by a foot of snow by end of Saturday, as one of the strongest storms in recent years causes transportation chaos, power outages

More than 60 million people are under bad weather warnings, from Maine to South Carolina; officials say they're working to ensure delivery of shots is not interrupted

Category 1 storm with 140 kph winds, set to also reach South Carolina, Washington, Philadelphia and New York; Florida escaped after Isaias hit Caribbean islands

Hurricane weakens to Category 4 storm, set to hit US East Coast after thrashing Caribbean island and putting much of Freeport, Grand Bahama underwater