Investigators are seeking the cause of a grass fire that burned nearly 5 acres of abandoned agricultural land on the outskirts of Phoenix in the middle of the night.

Callers from the Barnum Drive area called 9-1-1 to report the fire around 12:30 a.m. today.

Crews from Medford Fire Department, Jackson County Fire District No. 5 and the Oregon Department of Forestry responded to corral the flames, which neighbors estimated came to within 200 feet of homes.

Cool nighttime temperatures and light winds helped crews bring the fire under control quickly. A forestry department bulldozer cut a fire line around the blaze and an irrigation canal and railroad helped form natural barriers, Medford Fire Marshal Greg Kleinberg said.

Investigators were on the scene this morning to examine burn patterns and look for evidence about how the fire started.

Kleinberg said it could have been started intentionally or could have escaped from a homeless campsite. Campsites were found in the area along the canal where officials suspect the fire started, he said.

The flames spread to the north and west from the canal through abandoned orchards and farmland where weeds have shot to more than six feet in height and blackberry brambles lie in tangled masses.

The blaze lit up the night sky and attracted residents who watched nervously as fire crews and equipment flooded their neighborhood.

— Anita Burke