A 500-acre wildfire that burned within yards of several former plantation homes in Wahiawa yesterday appears to have been intentionally set, a Honolulu Fire Department spokesman said.

Fire investigators say the fire is suspicious because a witness reported seeing people in the area just beforehand and because there weren’t other apparent ignition sources, said fire Capt. Terry Seelig.

The fire started at about 1:30 p.m. behind several Poamoho Camp homes in a former pineapple field overgrown with 10-foot tall California grass. The blaze quickly spread across the field.

Residents scrambled to fight back 15-foot-high flames that came within about 30 yards of their homes. They turned on water hoses, dumped buckets of water and even beat back the fire with a shovel.

Malama Sua heard the trees crackling and looked up to see the flames. He yelled out a warning, then turned on three of his neighbors’ hoses, throwing them outward toward the flames. Then he ran toward his daughter’s house down the street and picked up a shovel somewhere along the way.

"I came with the shovel, and I hit with the shovel right here," he said, pointing to a patch of dirt just feet away from the blackened grass and ash.

Residents were rattled that it was the second encounter with a large fire in about two months. In July, a fire that started with an electrical short destroyed the camp’s clubhouse.

Dianne Minter was relieved her husband had dug up firebreaks and kept the grass mowed in her back yard to create a barrier between the tall grass and her house.

"It was really scary," she said. "I’m amazed that it stopped."

Residents in the 90-acre camp are in the process of buying the 66 homes and plan to turn the land that burned over to a farmer to grow sweet potatoes, Minter said.

Seelig said the flames were kept at bay by the quick response from firefighters, the action of residents and residents’ preventive measures, such as keeping grass short or removing clutter in the yard.

He said nine fire companies, six tankers and two helicopters worked on extinguishing the fire during the day, while a smaller crew was to stay overnight to monitor the blaze.

Police closed Wilikina Drive and Kaukonahua Road at Kamananui Road about 1:30 p.m., leading to miles of lumbering traffic around Wahiawa during afternoon rush hour. All roads were reopened by 9:10 p.m.

By about 7 last night, the fire had slowed and moved into a gulch, where it was difficult to reach. Seelig said firefighters will return at dawn today to assess the fire and build firebreaks with bulldozers.