Floods also overtook the transmitter for WDSU, a New Orleans TV station. A borrowed one, powered by a diesel generator to reach a tower on higher ground, allowed the station to broadcast. But news director Anzio Williams said his target audience wasn't the people who remained in New Orleans -- they had no electricity to power their television -- but evacuees and people across the world anxious about the Crescent City's fate.
So the station's broadcasts also stream over the Internet.
"We are still broadcasting in New Orleans, but who can see us here?" he shouted into his cellphone as he drove through a dry part of town. "People all over the country who had to move out of the city are watching us on computers."
That people turn to their Web browsers during major news events is a fact of the Digital Age. Newspaper circulation and television viewership both surge too. But the Internet differs from those media because it's interactive, making it almost as easy to contribute to news coverage as it is to consume it.
"Traditional journalism provides the view from the outside looking in, and citizen journalism provides the view from the inside looking out," said Mitch Gelman, senior vice president and executive producer of CNN.com. "In order to tell the complete story, you need both points of view."
And it gets easier every day.
The number of computers using high-speed Internet connections in the United States grew from less than 3 million in 1999 to nearly 38 million at the end of 2004, making online video and audio available to more people. Simple software has given rise to millions of personal Web pages and blogs. By one estimate, a new blog comes online every 7.4 seconds.
"For a long time [the Internet] was kind of an elite nerd club, if that's not an oxymoron," said John R. Levine, author of "The Internet for Dummies."
The engineers who created the network had no "idea how deeply it would become embedded in the popular society," Levine said. "If you had asked them 30 years ago if this is what they would like their network to be able to do, they would have said yes. But if you asked them whether they expected this, then no, they wouldn't have thought it would become this ubiquitous so quickly."
Or so vital to so many people.
Those in the direct path of the storm lost Internet access along with phone, gas and electrical service. But once evacuated, many went online. The Red Cross has begun establishing Internet kiosks at its 200 evacuation centers. Public libraries that weren't destroyed or heavily damaged have extended hours for evacuees to access the Internet through public computers.
Jim Forrest, who is overseeing the Astrodome computer center, said the Katrina relief effort included the widest-ever spread of computers and Internet access to disaster victims. "Of course we've got more victims now, so the Web is the way to go," he said.
Jill Gatsby, 38, an artist in Hollywood who sobbed as she watched TV footage of the devastation, said, "If I wasn't pregnant, I would have been down there on the first day ripping people out of the water. I was sitting here helpless."
Frustrated, she turned her personal website into a clearinghouse for information about Los Angeles-area places to donate clothing, food and other supplies. She said she received more than 350 calls in 24 hours after posting a message on Craigslist.
"Now I feel at least that I'm doing something," she said. "The Internet is pretty amazing."
Demand for online information about the storm's aftermath has been overwhelming -- much as it was during the London subway bombings or the Southeast Asian tsunami. After each of those news events, online news executives noticed that traffic remained higher than before the headlines, meaning people keep coming back to get more-mundane news.
Neil Budde, general manager of Yahoo News, attributed traffic increases after the hurricane to the complex stories involving thousands of people across a vast region. "That's a really tough story to tell on television because you've got such a narrow capability to get the story out."
Many television outlets used the Internet in ways they never had before. MSNBC.com created one of the largest online, searchable lists to help people connect with missing friends and family. As of Friday, 170,000 people had posted entries in the "looking for" and "safe" lists, which had been viewed more than 7 million times.
A "Katrina blog," written by reporters in the field, garnered more than 4,000 comments from visitors, many with offers of help. After an entry was posted about a baby who needed specialized infant formula, readers of the blog provided it.
Said MSNBC.com general manager Charlie Tillinghast: "It takes a crisis like this to turn something that has been mostly in the political space, with people trading opinions, into something that has been used for a humanitarian purpose."
Times staff writers David Colker, James S. Granelli, Scott Martelle, Joseph Menn, Martin Miller and Tony Perry contributed to this report.