Albuquerque, N.M. ? Residents returned to their homes along the Rio Grande Thursday as firefighters tried to stamp out the remnants of a smoldering blaze that transformed a riverside forest into a patchwork of black and gray.

The suspected arson fire began Wednesday night and scorched 700 to 800 acres. About 200 people were forced to abandon their homes and spent the night in hotels or the homes of friends and relatives.

Marlene Roberts fled her home with her husband, David, after he placed garden sprinklers on the roof.

“We could see these huge flames, and then you’d see just huge fireballs and these loud explosions. It was so eerie, both fascinating and terrifying at the same time,” she said.

About 200 firefighters were on the scene Thursday as two National Guard helicopters dumped massive buckets of water on remnants of the blaze. Crews also quelled a flare-up during the afternoon.

The fire was the second in the Rio Grande area in as many days. The first, just to the south, burned 701 acres after it began Tuesday.

Investigators were looking for two juveniles who might have set off fireworks that sparked the first fire, and for an adult who may have been responsible for the second blaze, said Mayor Martin Chavez.

Gov. Bill Richardson Thursday ordered a 19-mile stretch of the heavily wooded Rio Grande region closed through July 4.

A helicopter drops water on a hot spot in a forested area on the west side of the Rio Grande, in Albuquerque, N.M. A suspected arson fire that charred about 800 forested acres along the Rio Grande was contained Thursday after helicopters dropped water to quell the flames.