The area consumed by the fires reached 1,373 hectares as of early Sunday morning, up 7% from a day earlier.

The fires threaten residential districts of Otsuchi on the Pacific Coast – a town that lost nearly a tenth of its population in one of Japan’s worst disasters, the March 2011 earthquake and tsunami.

Evacuation orders are in place for 1,541 households or 3,233 residents, roughly a third of Otsuchi’s population.

“Although the Self-Defence Forces are fighting the fires from the sky (with helicopters), the dry weather and winds are helping the fires expand,” Otsuchi Mayor Kozo Hirano told a press conference.

One Otsuchi resident said he worried about the damage the wildfire could inflict.

“A fire burns everything down. With a tsunami, you might have something left after the destruction,” Yoshinori Komatsu, 74, said as he watched Self-Defence Force helicopters dump water over fires in the distance.

The only casualty to date has been one minor injury suffered when a person fell at an evacuation centre, Japan’s Fire and Disaster Management Agency said on its website.

No rain is expected in the region on Sunday or Monday, but a brief shower is forecast on Tuesday, according to the Japan Meteorological Agency.

The cause of the fires is unclear and under investigation.