Hurricane Ike has closed in on the Texas coast, pushing a wall of water that weather officials warned could be fatal for those who did not flee inland.
Waters rose rapidly as Ike moved within hours of striking low-lying areas near Houston with a possible six-metre storm surge in what may be the worst storm to hit Texas in nearly 50 years.
The National Weather Service warned that people in coastal areas could "face the possibility of death" from a massive storm surge.
Although Ike is weaker than 2005's Hurricane Katrina, the last storm to pummel a US urban area, its large scope gives it more water-moving power.
Ike was a Category 2 storm with 165 kilometres per hour winds as it moved on a course to pass directly over Houston, the nation's fourth-largest city.
Ike was expected to come ashore overnight, possibly as a dangerous Category 3 storm on the five-step intensity scale with winds of more than 178 kilometres per hour, the National Hurricane Centre said.
Ports were closed and the Coast Guard said a 178-metre freighter with 22 people aboard was stranded without power 145 kilometres south-east of Galveston.
Conditions were too treacherous to attempt rescue.