Earlier Tuesday, President Obama urged Americans to donate to the Red Cross in a speech from the White House.
"You can go online right now to the American Red Cross, which is already on the ground in Moore," Obama said. "Already we've seen the University of Oklahoma announce that it will provide housing for displaced families. We've seen local churches and companies open their doors and their wallets."
The storm killed at least 24 people, according to the Oklahoma medical examiner's office. Hundreds more were undergoing treatment at local hospitals, and rescue crews continue to search through the rubble for other survivors. The National Weather Service said the tornado saw winds of up to 200 mph and, at its peak, was nearly 2 miles wide.