Authorities in central Japan Thursday ordered tens of thousands to flee their homes after rains flooded rivers and triggered landslides, with one person missing after a mudslide buried houses.

The Japan Meteorological Agency issued special downpour warnings for Tochigi and Ibaraki prefectures, north of Tokyo, urging vigilance against mudslides and flooding.

“This is a scale of downpour that we have not experienced before. Grave danger could be imminent,” meteorologist Takuya Deshimaru said at an emergency press conference.

Parts of central Tochigi have been deluged with almost 60 centimetres (two feet) of rain since Monday evening.

Authorities in Tochigi ordered more than 90,000 residents to evacuate, while another 80,000 were advised to leave their homes, public broadcaster NHK said.

The meteorological observatory in Tochigi said the Kinugawa river, which also runs through Ibaraki, overflowed early Thursday.

In Tochigi’s Kanuma city, a local official said rescuers were searching for a missing person believed to be buried in mudslides.

“We don’t know details of the person yet,” he said.

NHK reported it was a woman in her 60s buried after mudslides destroyed houses.

Her husband was rescued soon after, it said.