Hurricane Harvey is currently a few hundred miles south of Texas, with it expected to reach land by 8pm CDT.
The hurricane is forecast to develop into a major category 3 hurricane later on Friday, August 24, the third most powerful on the Saffir-Simpson scale.
This would make it the strongest hurricane to hit the US mainland in 12 years.
Families living along the Texas coast are scrambling to fill up sandbags, stock up on supplies and boarding up their properties as Hurricane Harvey approaches.
Footage shows queues of cars as people try to flee the area or gather supplies from local businesses.
Several cities are handing out free sandbags so residents can protect their homes.
The Saffir-Simpson Hurricane Wind Scale says: “Well-built framed homes may incur major damage or removal of roof decking and gable ends.
“Many trees will be snapped or uprooted, blocking numerous roads. Electricity and water will be unavailable for several days to weeks after the storm passes.”
Texas Governor Greg Abbott has declared a state of disaster for 30 Texan counties, including Austin, Calhoun, Jefferson and Winsome counties.
Governor Abbott said: “I strongly urge all Texans to heed warnings from your local officials.
“I also urge that you immediately follow evacuation orders from all impacted counties, particularly in Corpus Christi and Houston where the storm surge and flooding from Hurricane Harvey are most likely.
“Please take all necessary precautions to save your life and minimise risk.”
Hurricane Harvey will be the first hurricane to hit Texas since 2008 when Hurricane Ike killed 21 people in Texas, Louisiana and Arkansas.