A fire behind warehouses and businesses at NE First Street and NE Olney Avenue in Bend burned a homeless encampment and caused exterior damage to businesses Sunday night.

A business owner was working inside around 9:30 p.m. when she heard several loud bangs outside and saw ash falling. The fire, which burned an encampment behind the building, caused minor damage to two buildings. Damage to one of the buildings, at 147 NE Olney Ave., is estimated to be $50,000.

Bend Fire & Rescue prevented the fire from spreading either to the inside of the business or to neighboring buildings.

The cause of the fire is unknown but believed to be related to the encampment. Several buildings involved also had wood, pallets, flammable vegetation and stored materials close to the buildings, which made it easier for the fire to spread. Juniper bushes close to one of the buildings caught fire, which spread to one of the windows.

Combustible vegetation should be kept at least 5 feet from buildings, the fire department said. The investigation is ongoing.