With forecasts showing Hurricane Sandy and another powerful storm system likely to collide with devastating effect somewhere on the Eastern Seaboard as early as Sunday evening, tens of millions of people began to make preparations, and authorities increased the urgency of their warnings.
Several states declared emergencies, and thousands of people were evacuated from low-lying areas. President Obama consulted with the leaders of the federal agencies that are monitoring the storm and will respond when it moves ashore. Governors in nine states deployed more than 60,000 National Guard troops to assist the local authorities.
Authorities said the weather conditions would deteriorate long before the center of the storm makes landfall, and that damage from widespread inland flooding, snow and wind could extend into the Ohio Valley, afflicting a third of the country.
"We're looking at impact of greater than 50 to 60 million people," said Louis Uccellini of the National Oceanic and Atmospheric Administration.
Gov. Chris Christie of New Jersey said that power could be out for more than a week if the forecasts hold, and he urged residents not to dismiss the warnings. He said. "We have to be prepared for the worst."
From Maine to North Carolina, people boarded up windows; stocked up on water, batteries, generators and food; and prepared to hunker down.
In New York City, Mayor Michael Bloomberg also urged residents to stock up and warned: "This is a large, unpredictable storm, so be prepared for possible outages."
Officials prepared for a possible shutdown of the subway and regional rail system and bridges in and out of the city.