Haiti has been placed on high alert as a powerful storm sweeps in, threatening thousands of earthquake survivors still living in camps. Forecasters say Tropical Storm Tomas is gaining strength and will begin to lash Haiti by late Thursday, reaching full force by Friday. Some camps are being evacuated and officials have told those living in tents to move to stronger shelter. Health workers fear heavy rain will exacerbate Haiti's cholera epidemic. The World's Katy Clark has more.