Japanese weather officials have changed a heavy rain emergency warning for Yamagata prefecture to a warning. They have kept in place the highest level-5 alert for Niigata Prefecture. People are advised to exercise great caution.

Niigata is experiencing its heaviest rainfall in decades. It's highly likely serious disasters such as flooding and landslides have already occurred.

The Meteorological Agency switched an emergency warning for Yamagata in northern Japan to a warning on Thursday morning.

But officials are urging people to stay alert for possible flooding and landslides.

Footage shows that the Mogami River in Yamagata has flooded and houses and roads around the river are inundated.

The Meteorological Agency is calling on people to check their surroundings and do whatever necessary to protect their lives. That includes moving to a sturdy building nearby or to the second floor or higher of a building opposite a cliff or slope if it's dangerous to go outside.

Weather officials say more rainfall is expected in some parts of northern and central Japan.