Heavy rains pelted northern New Jersey on Wednesday afternoon, but down south, firefighters battling a massive forest fire spanning nearly 20 square miles were still waiting and hoping for a storm to hit.

"We do not know if we will get precipitation here. Right now, our plan is for no rain. If we get some rain, that just makes it easier for us," said Maris Gabliks, chief of the New Jersey Forest Fire Service.

The blaze, which is believed to have been touched off by a National Guard F-16 that dropped a flare during a training exercise Tuesday afternoon in the tinder-dry Pinelands region, sent walls of flame racing toward senior citizen communities, where elderly residents grabbed their pets and ran.

"It was as close to hell on Earth as you'll ever experience in your life," said Bert Plante, a spokesman for the New Jersey Forest Fire Service. Speaking in a trailer park where two homes were incinerated and others damaged, Plante said, "The wall of fire that came here was twice as tall as the trees, easily 80 to 100 feet in the air."

As of 6 p.m. Wednesday, the fire had burned about 13,500 acres, or almost 20 square miles, Gabliks said.

Only a third of the fire was contained, said Gabliks, who added that firefighters hoped to have the blaze under control by Thursday or Friday.

Meanwhile, about 6,000 people had been evacuated from 2,500 homes. That included 300 patients in three nursing homes who had been relocated without incident, said State Police Superintendent Col. Rick Fuentes.

About 115 people remained in shelters on Wednesday evening, down from about 600 in the morning, Fuentes said.

More than 600 firefighters, some called from as far away as 30 miles, were using helicopters, water tanker trucks, bulldozers and other equipment to try to contain the fire, which was burning in the New Jersey Pinelands west of the Garden State Parkway.

The Parkway, one of the state's main north-south routes, was closed for a time Wednesday in the vicinity of the fire because dense smoke from the fire was making it difficult for motorists to see. It was reopened for the entire length Wednesday afternoon.

Authorities downgraded their count of homes damaged by the flames to 13, down from 50 Tuesday night. A closer inspection revealed that many of the houses that were believed to have suffered damage were not structurally harmed.

Five homes in two senior citizen housing developments in Barnegat were destroyed.

Plante said he expected up to 17,000 acres to be scorched before the fire is extinguished.

Dry conditions and strong winds helped fan the blaze, which began Tuesday afternoon on a military aerial bombing range about 25 miles north of Atlantic City.

Two state forest fire officials suffered minor injuries, but no serious injuries or deaths were reported.

However, some of those evacuated, many of whom are senior citizens, recalled frantic flights from the blaze.

"I didn't grab anything but the cat and myself, and we scrammed," said Helen Sura, who evacuated a housing development in Barnegat.

She and her cat, the aptly named Smoky, spent a sleepless night in her car in a Burger King parking lot.

"I was freezing because I didn't think to grab a sweater or a blanket," she said. "I figured we'd be back home in a few hours at most."

Eileen Papini also grabbed her cat, Puddycat, and fled the advancing flames.

"The smoke was so bad you couldn't see your hand in front of your face," she said.

Her trailer park, Pinewood Estates in Barnegat, suffered serious damage, authorities said. Several mobile homes there were damaged by the blaze. Papini was wondering if hers was among them.

"You don't know if you have a home to go back to," she said.

Evacuees described a rapidly advancing fire that mowed down everything in its path.

"It looked like big black clouds, lit up with orange fire, 40, 50 feet in the air, coming right toward you," said Stan Wesolowski of Barnegat. Like many other evacuees, he spent the night in his car rather than in one of several shelters set up in local schools. "It was a wall of flames coming right down the street."

Routes 539 and 72 were closed by the fire, which started about 2:15 p.m. Tuesday on the Warren Grove Gunnery Range, a 9,400-acre expanse of sand and scrub pine used for aerial bombing practice by Air National Guard units.

Lt. Col. James Garcia, a spokesman for the New Jersey Air National Guard, said it was believed a flare dropped from one its F-16s may have started the blaze, though an investigation was ongoing.

The range was the same facility from which a National Guard jet accidentally strafed an elementary school with large-caliber rounds in 2004 during a training exercise.

U.S. Sen. Frank R. Lautenberg complained Wednesday that the military hadn't followed up on safety pledges after the 2004 accident.

"This wildfire shows that the Air National Guard has not followed through on its pledge of increased safety," said Lautenberg, who said he would request a meeting with the Air Force and Air National Guard to address safety issues.

In 2001, an errant Air National Guard practice bomb caused a fire that burned more than 1,600 acres in the Pine Barrens.