The US city of Houston is in the grip of the biggest storm in the history of the state of Texas, officials say.
A record 30in of rain (75cm) has fallen on the city in the wake of Hurricane Harvey, turning roads into rivers.
The area is expected to have received a year’s rainfall within a week. Five people are reported dead. Helicopters have plucked victims from rooftops.
With rescue services overstretched as the rain continues, many people are having to fend for themselves.
Hospitals have been evacuated and thousands of people are without electricity.
Many schools are closed – as are the two main airports, with runways completely flooded.
Up to 2,000 people have been rescued in and around Houston, as the storm continues to batter Texas with heavy rains.
There are reports of possible deaths in submerged vehicles, but investigations continue, Chief Darryl Coleman of the Harris County Sheriff’s Office said.
The US National Weather Service (NWS) says conditions are “unprecedented”. A “flash flood emergency” in in force across the Houston area, with travel near impossible.
Harvey began as a category four hurricane but was later downgraded to a tropical storm. It is moving slowly and is expected to remain over Texas until the middle of the week.
Many shelters have been opened, including in a convention centre.
The Houston Chronicle has published a photo of an unidentified man in Houston trying to catch a fish as he wades through floodwaters in his living room.
One woman posted a picture online of two alligators in her backyard, while other photos show people water-skiing near the centre of the city.
Like Houston, the island city of Galveston was also hit by “epic catastrophic flooding” overnight, the NWS added.
An inundated care home in Dickinson, about 30 miles (50 km) south-east of Houston, is reported to have been evacuated by helicopter after an image of several elderly women sitting in a lounge in waist-deep water went viral on social media.
Help for flood victims
With the emergency services under intense pressure and complaints among some residents that emergency calls are not even being answered, hundreds of volunteers have made their way to Houston from all over the US.
They face difficult conditions because many of those stranded can only be rescued by air or by boat.
The US Coast Guard in Houston has requested more helicopters.
President Donald Trump is due to visit Texas on Tuesday to see the damage for himself. He signed a disaster proclamation on Friday, paving the way for federal cash to go towards the relief effort.
How serious is the flooding?
Forecasters have warned that it could worsen and become historic.
Insurance experts quoted by the Reuters news agency say it could equal the damage inflicted by Hurricane Katrina in 2005, widely reported to be the most expensive natural disaster in US history.
It was estimated that Katrina caused about $15bn of flood damage in the states of Louisiana and Mississippi.
But experts say at the moment it is too early to make detailed estimates of the damage in Texas.
Houston Mayor Sylvester Turner has urged residents not to call emergency services unless their situation is life-threatening and they need to be rescued.
“Don’t get on the road. Don’t assume this storm is over,” he said.
Officials in Harris County, of which Houston is the county seat, have asked boat owners to help with rescues.
Rescue efforts are also being hampered by strong winds. with some predictions that there will be a further 40in of rain before the storm subsides.
Houston is the country’s fourth biggest city, with 6.6m people living in the metropolitan area.
Meanwhile, Exxon Mobil has said it is shutting down the second-largest refinery in the country, at Baytown. The Texas Gulf Coast is a key centre of the US oil and gas industry.
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