Heavy rain has been falling across the Kanto region and the Izu islands since the night of November 4, with residents warned to prepare for rain-related disasters. Warm, humid air from Typhoon No. 31 has strengthened a low-pressure system and weather front off the Kanto coast, bringing intense downpours to Chiba Prefecture and the Izu islands.
Niijima village recorded about 300 mm of rain in 24 hours, its heaviest November total on record. A level 4 landslide danger warning was issued for the village, the second-highest on Japan's five-step evacuation scale.
Forecasters expect several more hours of intense rain. Landslides, flooded roads and swollen rivers are the immediate risks, along with lightning strikes, sudden gusts and disruption to transport.
Rain arriving late in the year
November rainfall records are unusual in a month that normally marks the start of Japan's dry, cool season. The warning follows a typhoon season that has already run into autumn, with a tropical depression that could become this year's 32nd typhoon now being watched, according to reports.