Hurricane Isaac has hit the US Gulf Coast, and forecasters are warning that tornadoes could appear over the states of Alabama, Mississippi, and Louisiana.<br /><br />The storm has already brought winds of up to 130 kilometres per hour.<br />In New Orleans, the city's flood system will get its first real test after Hurricane Katrina devastated the area exactly seven years ago.<br /><br />That's where Al Jazeera's Tom Ackerman is reporting.
