Authorities warned of heavy rain and possible tornadoes throughout Saturday as major storm Barry buffeted Louisiana, though there were few indications of widespread flooding.

After briefly becoming the first hurricane of the Atlantic season, Barry was downgraded to a tropical storm after making landfall -- but it nevertheless packed a serious punch as it moved inland.

All flights in and out of the airport in the state's biggest city New Orleans were cancelled, thousands had evacuated their homes, tens of thousands had lost power and first responders were poised for action.

Cajun Navy

The eye of the storm made landfall at Intracoastal City, a speck of a town with a few houses and businesses. Part of the main road was flooded Saturday afternoon, as were some waterfront businesses, with water rising by the minute.

News footage showed localized flooding, swollen waterways, and downed power lines and trees across south Louisiana as rivers overtopped their levees in several locations, including part of coastal Terrebonne Parish where authorities had issued a mandatory evacuation notice.

Thousands have packed up and left their homes as floodwaters hit low-lying areas like Plaquemines Parish, where road closures left some communities isolated.

Dangerous conditions

Louisiana is facing an extraordinarily dangerous confluence of conditions, experts say.

The level of the Mississippi River, already swollen from historic rains and flooding upstream, was at nearly 17 feet (5.2 meters) in New Orleans -- just below flood stage.

However, Edwards said new forecasts show many rivers wouldn't reach their maximum height predicted before the storm hit, though flash floods remained a threat.

US Senator Bill Cassidy said officials with the Army Corps of Engineers told him they were "confident" that the 20-foot-high levee system protecting New Orleans, a city of 400,000, would hold.

Agence France-Presse