Drought, Topography Hinders Firefighting Efforts in Ofunato; Majority of Japan’s Forest Fires Caused by People

By Shun Tomita, Fumiya Oshio and Morio Kodama / Yomiuri Shimbun Staff Writers

18:08 JST, March 3, 2025

A combination of prolonged dryness and strong winds has allowed a fire in Ofunato, Iwate Prefecture, to spread rapidly. As the risk of wildfires is feared to be increasing amid climate change, routine preparations and first-response firefighting have become more important than ever, according to an expert.

Minimal rainfall

“The flames spread quickly in the wind, and we were enveloped in black smoke. I couldn’t even see where I was,” said a 39-year-old office worker who leads a fire brigade in Ofunato, describing the tense situation immediately after the fire broke out.

The normal rainfall for Ofunato in February is 41 millimeters. But this year marked a record low of just 2.5 millimeters, and a dry air advisory had been in place since Feb. 18.

Shotaro Tanaka, who heads the Japan Meteorological Agency’s Center for Information on Climate Extremes, said behind the dry weather is the northern polar vortex – a region of cold, rotating air that normally sits above the North Pole – had split and one part had lingered near the Japanese archipelago. The seasonal winds from continental Asia had continued to blow for a long time, leading to the Pacific side of Japan being drier than usual.

The average wind speed in Ofunato was 7.7 meters per second (27.7 kph) at 1:30 p.m. on Wednesday when the fire broke out, and the maximum instantaneous wind speed was 18.1 mps (65.16 kph).

“Fire spreads 10 times faster when the wind speed is 6 mps (21.6 kph) than when it is 2 mps (7.2 kph),” said Koji Tamai, a research director at the Forestry and Forest Products Research Institute. “It is likely that fallen leaves and dead branches allowed the fire to spread quickly, as they had been dry for a long period of time.”

The fire expanded rapidly to consume over 600 hectares by 9 p.m., about eight hours after it broke out.

Mountainous area

About an hour after the fire started, the prefecture requested the Ground Self-Defense Force to be dispatched, but strong winds on that day kept the force from conducting water drops with its helicopters.

The area is surrounded by a ria coastline with mountains rising close by, and the Ofunato Fire Department said this topography makes it difficult for fire engines to approach many places.

Sufficient water could not be supplied by fire hydrants and fire cisterns, and the water pressure and volume would not be enough even if hoses are connected to pump water from the sea or rivers.

The number of fire brigade members in the city has declined by more than 300 over a decade to about 620 as of April 2024.

“Forest owners are aging and cannot take good care of their land, and that allows dead branches on the ground to pile up, causing fires to spread quickly,” said a forestry worker.

“Bonfire” most common cause

The number of forest fires peaked in 1974 at 8,351. Recently, around 1,300 fires occur each year, mainly the typically dry period between February and April, according to the Fire and Disaster Management Agency (FDMA).

Human factors are the predominant cause. The White Paper on Fire Service found that 32% of fires in 2023 were caused by bonfires, followed by 19% by controlled burns, 7.5% by arson and 3.8% by cigarettes.

A fire that burned 167 hectares in Ashikaga, Tochigi Prefecture, from February to March 2021 took 23 days to extinguish. Learning from the incident, FDMA called on municipalities in July 2022 to set up disaster management headquarters and create firebreaks along roads and rivers to protect homes. Even with all this in place, it is difficult to extinguish fires in cases where conditions come together to allow them to spread rapidly.

“The fact that aerial firefighting was impossible on the first day is thought to have been a major factor in the spread, but it was difficult to judge whether to request further support while assessing the situation, so I don’t think there were any major mistakes in how it was handled,” said Kazunori Kuwana, a professor at Tokyo University of Science. “Global warming and climate change will tend to lead to more extremes in weather and is expected to lead to more large-scale forest fires. We must examine the handling of the latest fire and come up with early-stage firefighting strategies. It is also important to prevent fires from breaking out in the first place.”