The US city of Houston is in the grip of an unprecedented flooding, which has turned main roads into rivers and making it impossible to move around other than by boats.

More than 30 inch (75cm) of rain has fallen on parts of the city this weekend, a BBC report said.

The city, which is facing the biggest storm in the history of the state of Texas, is expected to be deluged by a year's rainfall within this week.

Hundreds of roads have been closed across the city, hospitals have been evacuated and thousands of people are without electricity, the report said.

Up to 2,000 people have been rescued from floods in and around Houston, as Tropical Storm Harvey 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. Texas Governor Greg Abbott told the media he could not confirm reports of several storm-related deaths.

The National Weather Service (NWS) says conditions are "unprecedented". It said there was a "flash flood emergency" across the Houston Metro area, with travel near impossible.

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 back yard, while other photos show people water skiing near the centre of the city.

An immediate respite from Harvey's wrath seems unlikely to come. The National Weather Service warned things may become more dire if a forecasted record-breaking 50 inches of rain does fall on parts of Texas in coming days. In anticipation of a worsening situation, Dallas is turning its main convention centre into a "mega-shelter" that can host 5,000 evacuees, CNN said.