- The severe floods in the city of Zhengzhou have claimed at least 33 lives.
- In Anyang city, north of Zhengzhou, some areas received over 100 millimetres of rain.
- More than 500 people were rescued after two subway trains were submerged in Zhengzhou.
Piles of cars were strewn across a central Chinese city Thursday as shocked residents picked through the debris of a historic deluge that claimed at least 33 lives, with rescue efforts ongoing and hundreds seeking to find their relatives.
An unprecedented downpour dumped a year's rain in just three days on the city of Zhengzhou, weather officials said, instantly overwhelming drains and sending torrents of muddy water through streets, road tunnels and the subway system.
Hundreds of thousands of people in the area were also affected by the floods, with farmland inundated and road and rail links severed.
In worst-hit Zhengzhou, grim images of horror inside the subway system were relayed in real-time over social media, showing water rising during Tuesday's rush hour from the ankles of passengers to their necks.
At least a dozen people died before rescuers were able to cut survivors free from carriages.
Questions were swirling Thursday over how prepared authorities were for the disaster. Angry Weibo users questioned why the metro was not closed earlier, with one thread racking up more than 160 million views Thursday.
In a sign of mounting pressure, the transport ministry put out a statement ordering rail operators to "absorb the lessons of recent incidents", warning them to close stations quickly when faced with severe weather.
As the water retreated - with piles of cars a monument to its deadly power - residents prepared for the next wave of bad weather Thursday, moving vehicles to higher ground and trying to plot journeys out from the stricken city, where communications and power were still patchy.
With many streets still flooded, trucks pumped muddy water from underground tunnels as meteorologists issued "red" rain alerts, warning of the threat of fresh landslides and flooding in surrounding areas.
Residents queued to receive emergency water and instant noodles, as blackouts added to the challenges.
"I am waiting for the power to be restored, but it may take several more days I think," Chen, the owner of a local restaurant, told AFP.
- 'Lost everything' -
In Mihe township in Gongyi city - one of the worst-affected areas - residents surveyed the wreckage left behind as the rain stopped Thursday.
"I've lost everything, it's all been washed away. I had nothing to eat (while my house was flooded)," said a local resident, a middle-aged woman surnamed Song.
The human cost looked set to rise as rescuers scoured through debris.
An open-source spreadsheet, started by a student from Henan, was circulating on social media and listed hundreds of missing or stranded people across the province.
One woman whose relatives were listed on the spreadsheet told AFP that communications and power in the village near Gongyi county were both down, making it difficult to get information.
The state-run Global Times newspaper shared a video of rescuers pulling a three-month-old baby from a collapsed building in Zhengzhou.
The newspaper said the baby's mother was still missing.
- Topography, typhoon, climate -
Questions turned to how China's bulging cities could be better prepared for freak weather events, which experts say are happening with increased frequency and intensity due to climate change.
Anyang city, north of Zhengzhou, issued a red alert Thursday for heavy downpours after some areas received over 100 millimetres of rain, ordering schools to close and most workers to stay at home.
The changing climate is also making these kinds of extreme weather events more common as the world continues to heat up.
Henan province is striated by rivers, dams and reservoirs, many constructed decades ago to manage the flow of floodwater and irrigate the agricultural region.
But endless city sprawl is putting pressure on drainage.
State media rebuked suggestions that dams played a part in subverting the normal flow of water.