How to prepare for a hurricane Houston is one of the most populated metropolitan areas in the country and one of the fastest growing, according to the US Census Bureau.

The National Weather Service office in Houston warned flooding and winds could render parts of South Texas "uninhabitable for weeks or months."

And CoreLogic, an analytics firm, said Harvey, which developed into a Category 4 storm on Friday, could bring $20 billion worth of damage to metropolitan Houston alone.

Outer bands of Hurricane Harvey swipe Texas as more residents flee

Harris County, home to Houston, has issued voluntary evacuation orders for several communities near Trinity Bay. But Houston itself has not been put under an evacuation order.

"Right now, it appears that the Houston area will be spared the brunt of the hurricane force and the surge that goes along with it," said Gov. Greg Abbott at a press conference. "So that will minimize some of the danger."

Still, the governor encouraged people to consider evacuating.