"We're going to make sure you're not forgotten," Obama said as he and first lady Michelle Obama walked the streets of a reeling neighborhood. He said that although nothing could be done for the many who were killed - "they're alongside God at this point" - Obama assured support for resilient survivors.
Obama's comments came in the midst of a day of contrasts remarkable even for a president. From Alabama, Obama had planned to travel Cape Canaveral, Fla., to cheer the final launch of space shuttle Endeavour alongside injured Arizona Rep. Gabrielle Giffords. But that launch was called off suddenly Friday because of a technical problem.
Obama's schedule for the rest of the day was unclear, though the White House said the president was still expected to travel to Florida to deliver an evening commencement address at Miami Dade College.
As he traveled throughout Tuscaloosa, Obama absorbed the scenes of a community deeply deformed by the twisters, with trees uprooted and houses demolished. One young man told Obama he had witnessed debris lifting up all around him, yet he emerged with only cuts and bruises. "It's a blessing you are here," the president said back.
The nightmare storms in the South have killed about 300 people, chiefly in Alabama. Obama has stepped into the role of national consoler in chief before, including after the shooting of Giffords earlier this year, but he has not had to deal with the scope of such community obliteration until now.
"What's amazing is when something like this happens folks forget all their petty differences," said the president after spending time talking to the state's governor and Tuscaloosa's mayor. "When we're confronted by the awesome power of nature and reminded that all we have is each other."
The president said Tuscaloosa would rebuild in a way that would give him a story of pride he would tell all over the nation. He spoke with sleeves up rolled up under sunny skies, offering warm reassurances but no big display of emotion.
Visible from Air Force One as Obama neared a landing in Tuscaloosa: a long swath of tornado damage that looked like a wide, angry scar across the land. And as the president moved by motorcade through communities and business districts, suddenly the devastation was everywhere: flattened buildings, snapped trees, collapsed car washes and heaps of rubble, twisted metal and overturned cars as far as the eye could see.
Earlier, as he arrived in Alabama, Obama fell into lengthy conversations with Alabama Gov. Robert Bentley and Tuscaloosa mayor Walt Maddox before heading off to inspect the damage and spend time with local families and officials.
All told, the day had shaped up as an object lesson in the many roles a president must play, from healer to cheerleader, beginning with a nod to the country's civil rights past and ending with a speech to its future in a class of graduating students. Before departing the White House, he met with participants in the iconic 1968 Memphis sanitation workers' strike. The president was to end his day with the evening commencement address at Miami Dade College.
The president has declared a major disaster in Alabama and ordered federal aid to assist with recovery efforts.
In Florida, a pivotal swing state for Obama's re-election hopes, the president had been ready to act as cheerleader-in-chief for NASA's second-to-last space shuttle launch and for Giffords' encouraging if gradual recovery after she was shot in the head in an assassination attempt in Tucson, Ariz., in January.
Giffords' husband, Mark Kelly, was commander of the scheduled shuttle flight, and the president had Mrs. Obama and their two daughters with him, the first time an entire presidential family had planned to view a launch.
Although the shuttle program was ended by Obama's predecessor, George W. Bush, Obama has angered some NASA workers with his own space plans. He canceled Bush's proposed replacement for the shuttle program - a new mission to the moon - putting in its place vaguer plans for sending astronauts to land on an asteroid and ultimately Mars.
Obama wants private companies to pick up the shuttle's role of delivering payloads to the space station, an approach that is costing thousands of government jobs, including 2,000 contractors to be laid off after the final shuttle flight in June.
More than 500 employees lost their jobs earlier this month.