Floods kill at least 25 in China's Henan province

About 100,000 people have been evacuated in Zhengzhou, a city of 12 million.

This report produced by Zachary Goelman.

At least 25 people have died in China's Henan province after three days of rain matched what one weather bureau said was a level seen only "once in a thousand years." State media reported several people drowned inside a flooded subway tunnel in the provincial capital of Zhengzhou, where more than 500 were pulled to safety.

Footage from state broadcaster CCTV showed commuters deep in murky floodwaters, and an underground station flooded close to the ceiling.

This man said he had to fight to stay alive.

(SOUNDBITE) (Mandarin) ZHANG, PASSENGER AFFECTED BY FLOODED SUBWAY, SAYING: "The flood was so strong and many people were carried away by that.

The remaining few of us including a kid were so tired, and we nearly gave up.

We kept holding on tight to the railing, that's why you can see many bruises on my arms. These are all the bruises, this is one too, this included too.

If you don't hold on tight to that railing, it's very easy to be washed away." About 100,000 people have been evacuated from the city of 12 million.

Dams and reservoirs have swelled to warning levels and more rain is forecast across Henan for the next three days.

The People's Liberation Army has sent more than 5,700 soldiers and personnel to help with search and rescue.

Scientists told Reuters the rainfall in China, like extreme flooding recently seen in western Europe and heatwaves in the U.S. was almost certainly linked to global warming.