The blaze around the northern city of Ofunato has killed one person and forced nearly 4,000 to evacuate their homes.
It has engulfed around 2,900 hectares — over eight times the area of New York City’s Central Park — making it Japan’s largest wildfire since at least 1975, when 2,700 hectares burnt in Kushiro on Hokkaido.
But rain and snow were falling Wednesday as several columns of white smoke billowed from a mountain where the blaze has been raging.
“Firefighters have been working on the ground through the night to extinguish the fire,” a city official said on Wednesday.
“We are hoping that snow, which started to fall this morning, will help,” he added.
At least 84 buildings are believed to have been damaged, although details are still being assessed, according to the fire agency.
As of late Tuesday, almost 4,000 people living nearby had complied with orders to evacuate.
Japan endured its hottest summer on record last year, as climate change pushes up temperatures worldwide.
The number of wildfires in the country has declined since its 1970s peak, but there were about 1,300 in 2023, concentrated in the period from February to April when the air dries out and winds pick up.
Japanese baseball prodigy Roki Sasaki, who recently joined the Los Angeles Dodgers, has offered a 10-million-yen (US$67,000) donation and 500 sets of bedding to people affected by the wildfire.
Sasaki was a high school student there, after losing his father and grandparents in the huge 2011 tsunami. (AFP)
