After checking on his family's home, Henry Walker (R) plays around with friends Keron Roundtree (L) and Barry Gurley (C) as rapidly rising floodwaters covered in leaking kerosene fill a neighborhood in the South Ward district of Trenton, N.J. because of rain from Hurricane Irene August 28, 2011. [Photo/Agencies]

Rivers roared in New Jersey and Pennsylvania. In the Hudson Valley town of New Paltz, N.Y., so many people were gathering to watch a rising river that authorities banned alcohol sales and ordered people inside. And in Rhode Island, which has a geography thick with bays, inlets and shoreline, authorities were worried about coastal flooding at evening high tide.

The entire Northeast has been drenched this summer with what has seemed like relentless rain, saturating the ground and raising the risk of flooding, even after the storm passes altogether.

The storm system knocked out power for 4½ million people along the Eastern Seaboard. Power companies were picking through uprooted trees and reconnecting lines in the South and had restored electricity to hundreds of thousands of people by Sunday afternoon.

Under its first hurricane warning in a quarter-century, New York took extraordinary precautions. There were sandbags on Wall Street, tarps over subway grates and plywood on storefront windows.

The subway stopped rolling. Broadway and baseball were canceled.

With the worst of the storm over, hurricane experts assessed the preparations and concluded that, far from hyping the danger, authorities had done the right thing by being cautious.

Max Mayfield, former director of the National Hurricane Center, called it a textbook case.

"They knew they had to get people out early," he said. "I think absolutely lives were saved."

Mayfield credited government officials - but also the meteorologists. Days before the storm ever touched American land, forecast models showed it passing more or less across New York City.

"I think the forecast itself was very good, and I think the preparations were also good," said Keith Seitter, director of the American Meteorological Society. "If this exact same storm had happened without the preparations that everyone had taken, there would have been pretty severe consequences."

In the storm's wake, hundreds of thousands of passengers still had to get where they were going. Airlines said about 9,000 flights were canceled.

Officials said the three major New York-area airports will resume most flights Monday morning. Philadelphia International Airport reopened Sunday afternoon, and flights resumed around Washington, which took a glancing blow from the storm.