SAVANNAH -- The color of Savannah's weekend St. Patrick's Day celebration turned from green to pitch black late Saturday as the city and most of Chatham County lost power, plunging the downtown party into darkness as thousands roamed the streets.

The storms that dampened Savannah's biggest party of the year also blackened much of Liberty and Bryan counties, as electrical service lines in Effingham County were hit by a strong line of storms. The outage was confused in Hinesville when power in the western part of the city had been knocked out earlier when a vehicle reportedly hit a power pole, pulling down the line.

The only lights in the downtown historic district were flashing atop police cars as officers directed traffic amid throngs of revelers roaming streets littered with plastic cups and shouting "Paaartay!" and "Happy Blackout Day!"

"It's just people wandering around in the dark, man," said 23-year-old Danielle Smith of Savannah, looking for friends amid the confusion near the city's riverfront. "This is crazy!"

The blackout hit at about 10 p.m. as strong thunderstorms tore through southern Georgia and South Carolina just north of Savannah. Some 150,000 customers in the Savannah area were without electricity after transmission lines were knocked out by the storms in Effingham County, Georgia Power spokesman Jeff Wilson said.

Lights in the city started coming back on about 1 a.m. Sunday, he said.

By 8 a.m., about 70,000 customers were still without power, company spokeswoman Carol Boatright said. Crews worked throughout the night to restore power but were slowed by the darkness, she said.

Power in much of the rest of the region, which is served by other utilities including Coastal EMC, was restored over night.