170,000 evacuated as major, 'once-in-50-years' flooding hits Japan; homes washed away (video)

The raging brown floodwaters spawned from Tropical Storm Etau, which has dumped 60 centimeters (2 feet) of rain over some areas since Monday.

Combine that with several weeks of near-daily rainfall, and Ibaraki and Tochigi prefectures are now deluged and unrecognizable.

"Tochigi Prefecture is facing a grave danger and is in an emergency situation," Japan Meteorological Agency Spokesman Takuya Deshimaru said. "It is experiencing unprecedented downpour."

Thousands evacuated

More than 170,000 people have been evacuated, officials said. Those who didn't leave found their houses submerged within minutes. The latest evacuation advisory came for the city of Sendai, where more than 200,000 residents in three wards were warned they may need to leave their homes due to rising water.

Members of the Japanese Self Defense Forces dropped from helicopter lines to pluck stranded residents from their roofs. Two by two, they swung precariously over the raging currents as they were pulled back up to the aircraft...