Hanna is expected to dump 6 to 12 inches of rain, perhaps up to 18 inches in some areas, through Sunday night in south Texas and nearby Mexican states. The deluge could lead to life-threatening flash flooding, rapid rises on small streams, and isolated minor to moderate river flooding in south Texas. Areas along the upper Texas and Louisiana coasts — and inland to the Mexican states of Coahuila, Nuevo Leon, and northern Tamaulipas — can expect several inches of rain as well, forecasters said.