'This is a major disaster' - Hurricane Harvey makes landfall as thousands flee to safety
- Texas governor warns of 'major disaster'
- Ships unable to dock and left stranded
- Thousands flee path of Category 3 hurricane
- Hundreds of miles of coastline in Texas and Louisiana in path
- President Trump warns: 'Plan ahead'
Hurricane Harvey has strengthened to a Category 3 and is due to hit the southern US coastline late tonight or in the early hours of Saturday morning.
The US National Hurricane Center (NHC) warned that Harvey was "rapidly intensifying".
Wind speeds of up to 110mph are expected, with experts fearing it could be the worst storm to hit the mainland since Hurricane Katrina in 2005.
Mandatory evacuations were ordered for several cities on the Texas Gulf Coast.
"My urgent message to my fellow Texans is that if you live in a region where evacuation has been ordered, you need to heed that advice and get out of harm's way while you can," Texas Gov Greg Abbott said in a televised address.
He issued disaster declarations in 30 counties, saying the preemptive move would allow the state "to quickly deploy resources for the emergency response effort."
Forecasters also warned of a "life-threatening" storm surge as heavy rain was predicted along with the high winds. There could be as much as 30 inches of rain in some areas.
"With this system's intensity and slow motion, it is the worst of both worlds," John Tharp, a forecaster with Weather Decision Technologies in Norman, Oklahoma, told Reuters.
"There will be major impacts along the coast and inland with periods of prolonged rain."
In Louisiana, New Orleans is bracing itself for heavy flooding.
The storm is expect to hover over the city for many days.
An emergency declaration has been issued for the entire state and hundreds of boats were made available for potential rescues.
Carnival Corp said on Friday that three of its cruise ships are unable to return to the Port of Galveston, Texas, which is closed ahead of Hurricane Harvey.
Two of the ships, the Carnival Freedom and the Carnival Valor, will head for New Orleans where they will pick up fresh supplies. Passengers will have the option of disembarking there, but Carnival advised them to not do so and said the ships will return to Galveston as soon as feasible.
A third ship, the Carnival Breeze, will extend its stay in Cozumel, Mexico, and begin sailing back to Galveston this weekend, the company said.
The next scheduled cruises on all three ships will be shortened and customers will receive refunds, the company said.
"We will continue to remain in close contact with port officials regarding their plans to re-open once the storm has passed," spokeswoman Christine de la Huerta said.
With additional reporting from Reuters