OFFICIALS fear the death toll from flooding in Texas sparked by Hurricane Harvey could soar once the water recedes from one of America’s most sprawling metropolitan centres.

Crews have been overwhelmed by thousands of rescue calls during one of the heaviest downpours in US history and have had little time to search for potential victims.

More than three days after the storm ravaged the Texas coastline as a Category 4 hurricane, authorities had confirmed only three deaths, including a woman killed when heavy rain dislodged a large tree on to her trailer home in the small town of Porter, but unconfirmed reports of others missing or presumed dead are growing.

“We know in these kind of events that, sadly, the death toll goes up, historically,” Houston police chief Art Acevedo said. “I’m really worried about how many bodies we’re going to find.”

One Houston woman said she presumed six members of a family, including four of her grandchildren, died after their van sank into Greens Bayou in East Houston, although emergency officials have not confirmed the deaths.

The disaster is unfolding on an epic scale, with the nation’s fourth-largest city mostly paralysed by the storm

that has parked itself over the Gulf Coast.

With nearly 2ft more rain expected on top of the 30in that has fallen so far in some places, authorities worry the worst might be yet to come.