Hundreds of thousands of people were told to be on alert for "sudden" rises in river water levels on Thursday after significant warming heightened the risk of ice jams in the Omaha, Nebraska, area. National Weather Service (NWS) meteorologists issued a flood watch and a hazardous weather outlook for the Omaha forecast region early Thursday morning. The flood watch is in place for the Platte, Elkhorn, and Loup Rivers because of "potential ice jam development," the alert said. It will remain in