Now a tropical storm, Isaac slashed its way further inland, claiming its first fatality and stranding residents in flood-prone areas even as it threatened to wreak more havoc in the days to come.

A tow truck driver attempting to clear debris on a road in Mississippi was struck by a falling tree.

Although weakened and forecast to become a tropical depression by evening, the pounding rains are still drenching a large swath of the Gulf Coast.

Mississippi and Louisiana announced mandatory evacuations for all low-lying areas along the Tangipahoa River.

A dam at 700-acre Lake Tangipahoa has not breached but has been badly damaged by heavy rains.