Residents clears debris of a house destroyed by a tornado in Pleasant Grove,Alabama, April 29, 2011.President Barack Obama promised federal aid on Friday to the tornado-ravaged U.S. South after he got a close-up look at the "heartbreaking" impact of deadly twisters that occurred on April 27, killing at least 310 people. REUTERS/Tami Chappell (UNITED STATES - Tags: DISASTER ENVIRONMENT)