Hurricane Isaac 2012 Path: Half of Louisiana Without Power, Arkansas and Missouri Brace (Tracker Map)

Hurricane Isaac may have weakened to tropical storm strength but strong winds and heavy rainfall continue to pummel Louisiana, leaving nearly half of the state without power.

(Photo: NOAA/Handout)Hurricane Isaac's predicted path map as on Augu. 29, 2012.

More than 900,000 homes and businesses are without power on Thursday, according to the Public Services Commission, and most are likely to remain without power for a few more days as services wait for the storm to clear before restoration works can begin.

In Mississippi more than 150,000 customers have also been hit by outages, but utilities companies have promised they are doing all they can to restore power as soon as possible.

New Orleans' new multi-billion dollar flood defense system stood up to its first major test since Hurricane Katrina struck exactly seven years ago. However, the regions to the north and south of the city suffered on a much larger scale than when Katrina hit. Local flood defenses were overwhelmed by Isaac's heavy downpours, as well as its slow pace - meaning rainwaters flooded the areas for extended periods.

(Photo: Reuters/Michael Spooneybarger)A vehicle is submerged in flood waters in Jourdan River Shores neighborhood as Hurricane Isaac passes through Kiln, Mississippi, August 29, 2012.

Thousands of people had to be rescued and evacuated from New Orleans' surrounding areas. Along the shores of Lake Ponchartrain just north of New Orleans, dozens of buses and high-water vehicles were despatched to evacuate some 3,000 people as waters rose fast. According to the Associated Press water was waist-high in some areas.

The Louisiana National Guard was working with sheriff's deputies to rescue people stranded in their homes in Louisiana. The floodwaters "were shockingly fast-rising, from what I understand from talking to people," Lt Gov Jay Dardenne said. "It caught everybody by surprise."

Nearly a million people across four states in the region are now without power.

(Photo: NASA/NOAA/GOES Project/Handout)Hurricane Isaac is seen churning in the Gulf of Mexico after making landfall on the Louisiana coast in this NASA handout satellite image taken on August 28, 2012, at 21:55 EDT.

Early Thursday Isaac continued on its prowl northwards and targeted Baton Rouge, Louisiana as its main target. Despite weakening sustained wind speeds, Isaac's strength is still strong enough to cause significant problems for the region, especially with trees being felled and power outages. Isaac's weakened state, however, means most experts are predicting it will not cause anywhere near the type of devastating to the region as caused by Hurricane Gustav, which hit Baton Rouge four years ago.

Tropical Storm Isaac will continue to move over Louisiana over the course of Thursday, according to the U.S. National Hurricane Center (NHC), and Arkansas and Missouri will be next up to be hit by Isaac as it continues its northwards path.

The NHC has warned that despite its winds weakening, Isaac still poses a very real threat to life, and residents still within its path should exercise extreme caution. Strong storm surges, floods, and isolated tornadoes are still highly likely, according to the NHC.