The full horrors of monster storm Harvey began emerging Wednesday as the bodies of six family members were plucked from floodwaters in Texas and heavy rains pounded Louisiana.
The number of confirmed deaths linked to Harvey now stands at 23. Authorities are investigating 17 more deaths to determine whether they were storm-related, and they fear many more bodies may be found as floodwaters start receding.
While clouds parted in Houston, bringing welcome respite to a city where roads have become rivers, rural areas of Texas were drenched as Harvey headed eastwards.
Authorities in neighboring Louisiana meanwhile raced to safeguard their state from the impact of Harvey whose onslaught has evoked painful memories of Hurricane Katrina's deadly strike 12 years ago.
Taking advantage of a lull in the rainfall in Houston, rescuers recovered the bodies of six family members from a van which was swept away by the floods over the weekend.
Manuel and Belia Saldivar and four of their great-grandchildren ranging from six to 16 years in age went missing Sunday as they were attempting to escape rising waters.
"We have a total confirmed six dead here at the scene inside this van," Harris County Sheriff Ed Gonzalez told a press conference. "Our worst fears have been realised."
So far around 30 people are believed to have been killed in the storm, but with hundreds are still unaccounted for, there is little doubt the final toll will rise further - although officials stress many may simply have no access to phones or power.
"To those Americans who have lost loved ones, all of America is grieving with you, and our hearts are joined with yours forever," President Donald Trump said in a speech, a day after viewing some of the damage for himself on a trip to Texas.
"The citizens of Texas and the Gulf Coast need all the prayers, support, and resources our communities have to offer."
More than 30,000 people have found refuge in shelters across the Lone Star State, from the giant Houston convention center to small churches, according to the head of the Federal Emergency Management Agency (FEMA), Brock Long.
"We are in this for the long haul," acting Homeland Security Secretary Elaine Duke said at a briefing on emergency operations.
"We'll continue to support the people of Texas as long as necessary."
In Houston, Mayor Sylvester Turner issued an nighttime curfew aimed at aiding search efforts and thwarting potential looting in the flood-ravaged city, whose two major airports reopened Wednesday on a limited basis as floodwaters receded.
At least a quarter of Harris County, which includes Houston and the immediate surrounding area, is still under water, affecting tens of thousands of homes.
But the worst-hit areas on Wednesday were eastern parts of Texas, including the city of Port Arthur which was almost impossible to reach, despite the best efforts of volunteer rescues.
Justin Coleman, 33, drove overnight from Fort Worth, part of a crew of three jeeps and three boats, which were forced to turn around on their first attempt to reach the city.
"We're on the radio with them right now and every 30 seconds there's another person rescued," he told reporters during a pit stop at a gas station in the nearby town of Winnie.
"There's a lot of babies and elderly that are stuck in their homes right now. They said it's getting up to their chests," said Coleman who runs a construction company.
So far, parts of Texas have seen more than 50 inches (1.27 metres) of rain, while in Louisiana, the top total 18 inches so far - was increasing.
Harvey first slammed onshore as a Category Four hurricane on Friday night before unloading on Texas.
Although now downgraded to being a tropical storm, Harvey made its second landfall just west of the Louisiana town of Cameron early Wednesday, packing maximum sustained winds nearing 45 miles per hour.
Forecasters are predicting another five to 10 inches of rain in the region, with the downpour finally expected to stop on Thursday.
For now, south western Louisiana is taking the hardest hit, with a levee being breached in the town of Gueydan.
New Orleans, the state's biggest city, appeared to have dodged a bullet, with minimal rain.
But the arrival of Harvey nevertheless served as a sombre reminder coming just one day after the 12-year anniversary of Katrina, which ravaged the vulnerable city famous for its jazz music and cuisine.
"I began to pray for the people in Texas after having gone through that same experience myself as a Katrina survivor," said Crystal Harris, who works for a bank which was taking donations for storm victims.
In Texas, emergency crews were still struggling to reach hundreds of stranded people in a massive round-the-clock rescue operation, as the National Weather Service predicted weather conditions there were to improve at last.
But the damage wrought was staggering - Enki Research put its "best estimate" at between $48 billion and $75 billion.
At least one bridge had crumbled, one levee had breached and dams were at risk in Texas.
More than 4,500 people and 1,000 pets have been rescued from the storm zone by the Coast Guard, which expects to rescue an additional 1,000 people Wednesday in the Port Arthur area alone.
The Coast Guard has deployed about 50 aircraft and two dozen boats in the operation, but the overall rescue effort, involving other military branches and state police, easily tops more than 100 aircraft.
"This has been a hurricane a day for six or seven days," Admiral Paul Thomas, who oversees Coast Guard operations in 26 states, told reporters in New Orleans.
"We are certainly bringing lessons learned from Katrina," added Thomas while noting that several members of his team are Louisiana natives who are veterans of the 2005 disaster.
The US Gulf Coast is a major hub of America's oil industry, accounting for 20 per cent of the country's crude production.
Harvey sparked the closure of several major refineries. Many rigs were also knocked out. On Wednesday, crude prices were down at the opening in New York.
