AT LEAST one person has been confirmed dead as former Hurricane Harvey rolled over the Texas Gulf Coast, smashing homes and lashing the shore with wind and rain so intense that drivers were forced off the road.
Rockport Mayor Charles J. Wax said the storm had so far claimed one life. The unidentified victim, from Rockport, Texas, was trapped when a fire broke out during the storm.
The fiercest hurricane to hit the US in more than a decade came ashore late on Friday about 48 kilometres northeast of Corpus Christi as a mammoth Category 4 storm with 209km/h winds. As of 4am AEST it had weakened to a tropical storm travelling at about 70km/h.
Locals were also warned of alligators turning up outside homes as they search for higher ground after being displaced.
But the storm's most destructive powers were just beginning, with Texans bracing for "walls of water" and a $US40 billion ($50.5 billion) damage bill.
"Catastrophic" rainfall that will continue for days could dump more than 40 inches (100cms) of water and inundate many communities, including dangerously flood-prone Houston, the nation's fourth-largest city.
"Our focus is shifting to the extreme and potentially historic levels of flooding that we could see," said Eric Blake, a specialist at the National Hurricane Centre in Miami.
POWER CUTS, DESTRUCTION
While only one person has been confirmed dead so far officials fear the death toll could go much higher with high winds keeping emergency crews out of many places.
Authorities said it could be hours before emergency teams are able to fully assess damage due to rising floodwater.
Texas Governor Greg Abbott said his primary concern remains "dramatic flooding" in his state, and warned residents to be on guard for rapidly rising water.
More than 330,000 residents were without power in the coastal region, and nearly 20 inches (50cms) of rain had fallen in some places.
Mayor Wax of Rockport, a coastal city of about 10,000 that was directly in the storm's path, said his community took a blow "right on the nose" that left "widespread devastation," including homes, businesses and schools that were heavily damaged. Some structures were destroyed.
Mr Wax told T he Weather Channel that the city's emergency response system had been hampered by the loss of mobile phone service and other forms of communication.
About 10 people were taken to the county jail for treatment after the roof of a senior housing complex collapsed, television station KIII reported.
On Friday, Rockport councilman Patrick Rios offered ominous advice, telling the station that people who chose not to evacuate should mark their arm with a Sharpie pen, implying that the marks would make it easier for rescuers to identify them.
As many as six million people were believed to be in Harvey's path, as is the heart of America's oil refining operations.
CoreLogic estimates the reconstruction costs of homes could reach $US39.6 billion ($50.5 billion).
In the storm's immediate aftermath, the Coast Guard sent two helicopters to try to rescue the crews of three tugboats reported in distress in a channel near Port Aransas.
By late morning, Harvey's maximum sustained winds had fallen to about 120km/h and the storm was centred about 40 kilometres west of Victoria, Texas. It was moving north at 3km/h according to the hurricane centre.
The system has since become tropical storm.
The hurricane posed the first major emergency management test of US President Donald Trump's administration.
The president signed a federal disaster declaration for coastal counties on Friday night.
He commended the head of the Federal Emergency Management Agency for his handling of the storm.
In a tweet Saturday morning addressed to FEMA head Brock Long, Mr Trump said: "You are doing a great job - the world is watching! Be safe."
Closely monitoring #HurricaneHarvey from Camp David. We are leaving nothing to chance. City, State and Federal Govs. working great together!— Donald J. Trump (@realDonaldTrump) August 26, 2017
In a separate tweet, Mr Trump said he is monitoring the hurricane closely from Camp David.
"We are leaving nothing to chance. City, State and Federal Govs. working great together!" The president also tweeted, "We have fantastic people on the ground, got there long before (hash) Harvey. So far, so good!"
In Corpus Christi, the major city closest to the storm's centre, wind whipped palm trees and stinging sheets of horizontal rain slapped against hotels and office buildings along the seawall as the storm made landfall.
Daybreak revealed downed lamp posts and tree limbs and roof tiles torn off buildings.
The city's marina was nearly unscathed, save an awning ripped from a restaurant entrance and a wooden garbage bin uprooted and thrown.
Along Interstate 45 leaving Galveston, motorists had to stop under bridges to avoid driving in white-out conditions.
Fuelled by warm Gulf of Mexico waters, Harvey grew rapidly, accelerating from a Category 1 early Friday morning to a Category 4 by evening.
Its transformation from an ordinary storm to a life-threatening behemoth took only 56 hours, an incredibly rapid intensification.
Corpus is fine, the eye of the hurricane hit rockport. I drove to go see the damage but the streets were too flooded and this is all I got pic.twitter.com/QhT58zfExO— Juan (@Juan_Pann) August 26, 2017
Harvey came ashore as the fiercest hurricane to hit the US in 13 years and the strongest to strike Texas since 1961's Hurricane Carla, the most powerful Texas hurricane on record.
Before the storm arrived, property owners raced to nail plywood over windows and fill sandbags. Steady traffic filled the highways leaving Corpus Christi, but there were no apparent jams.
In Houston, where mass evacuations can include changing major highways to a one-way vehicle flow, authorities left traffic patterns unchanged.
Harvey's approach sent tens of thousands of people fleeing inland. But just hours before the projected landfall, the governor and Houston leaders issued conflicting statements on evacuation.
After Governor Greg Abbott urged more people to flee, Houston authorities told people to remain in their homes and recommended no widespread evacuations.
In a Friday news conference that addressed Houston officials' decision to not have a voluntary or mandatory evacuation, Houston Mayor Sylvester Turner said there might be a "greater danger" in having people who don't need to be evacuated on roads that could flood.
Harris County Judge Ed Emmett said that because the hurricane was not taking direct aim at Houston, the city's primary concern was heavy flooding.
"We are not having a hurricane," said Emmett, the top elected official for the county, which encompasses Houston. "We are having a rain event."
All seven Texas counties on the coast from Corpus Christi to the western end of Galveston Island ordered mandatory evacuations from low-lying areas. Four counties ordered full evacuations and warned there was no guarantee of rescue for people staying behind.
State officials said they had no count on how many people actually left their homes.
TEXAS STARTS TO ASSESS DAMAGE
One woman has posted a video of the heavy seas which she says sank the tugboat her husband was aboard off the coast of Rockport.
He had earlier managed to contact her saying he and the crew of two tugboats had abandoned their vessel, and had lashed themselves to the barges they had been towing. They have not been heard of since.
Rockport Volunteer Fire Department spokeswoman Gillian Cox has told the Corpus Christi Caller-Times that the roof of Rockport's high school has partially caved in.
Rockport City Manager Kevin Carruth tells the newspaper that the courthouse in the city about 48 kilometres northeast of Corpus Christi also has sustained major damage.
Mr Carruth says that a cargo trailer is halfway in the building.
He says 10 people have been taken to the county's jail for assessment and treatment after the roof of a senior housing complex collapsed.
Rockport's historic downtown area also has seen heavy damage, he says.
Volunteer Fire Department Chief Steve Sims says there are about 15 volunteer firefighters hunkered down at the city's fire station waiting for conditions to improve enough for their vehicles to safely travel and to assess the damage to the city of about 10,000 people.
"There's nothing we can do at this moment. We are anxious to get out there and make assessments, but we're hunkered down for now," he said.
"We've heard rumours of 1000 different things, we can't confirm anything because we haven't seen anything. We know we've got a lot of problems, but we don't know what yet."
Officials about 16 kilometres away in Aransas Pass say the Harbor Master Building along its coast has been destroyed.
The Aransas Pass Police Department posted a video on its Facebook page of the building folding up from the high speed winds.
Melissa Munguia, deputy emergency management co-ordinator in Nueces County, which includes Corpus Christi, said that it could be hours before crews could fully assess the damage in coastal communities.
Some 200,000 people are without power in Corpus Christi and surrounding areas.
Meanwhile, the US Coast Guard has pulled 12 people off a tugboat via helicopter under extreme wind north of Port Aransas after the vessel lost power.
The last Category 4 storm to hit the US was Hurricane Charley in August 2004 in Florida. Superstorm Sandy, which pommeled New York and New Jersey in 2012, never had the high winds and had lost tropical status by the time it struck. But it was devastating without formally being called a major hurricane.
Harvey is the first significant hurricane to hit Texas since Ike in September 2008 brought winds of 177km/h to the Galveston and Houston areas, inflicting $US22 billion ($27.7 billion) in damage.
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