Donald Trump has signed a disaster proclamation as he faces his first major emergency as President.
Billed as the strongest hurricane to hit the US in 12 years, Hurricane Harvey landed on a stretch of coastline near the town of Rockport at around 10pm local time (4am UK time) bringing “life threatening” winds of 130mph.
Power to some homes was knocked out, and signs and pieces of palm tree littered the streets as the category 3 storm took hold.
There are also reports of roofs collapsing into houses, trees being uprooted and buildings being destroyed.
The storm is expected to dump more than 3ft (90cm) of rain along the Texas coast and parts of Louisiana over several days.
Harvey has been compared to one of America’s deadliest storms – Hurricane Katrina – which killed more than a thousand people in New Orleans in 2005. New Orleans does not lie in Harvey’s direct path.
Donald Trump wrote on Twitter: “At the request of the Governor of Texas, I have signed the Disaster Proclamation, which unleashes the full force of government help!”
The President is currently in Camp David “closely watching the path and doings of Hurricane Harvey”.
He earlier encouraged everyone in the path of the storm “to heed the advice and orders of their local and state officials”.
The National Hurricane Center described the storm as “life-threatening, dangerous and catastrophic”.
Sky News Correspondent Siobhan Robbins took shelter with some residents forced to leave their homes in the city of Corpus Christi on the Gulf of Mexico.
She said: “Officials have warned that this storm could cut off power and water and homes could be uninhabitable for months.
“Thousands have already been evacuated, but the worry is that people have heard all this before and still aren’t getting themselves to safety.”
Mayor of Rockport, Patrick Rios, warned residents remaining in the area to “mark their arm with a Sharpie pen with their name and social security number” to make it easier for rescuers to identify them.
Seven counties in Texas have ordered mandatory evacuations, and tens of thousands of people left their homes ahead of the storm’s arrival.
Petrol prices shot up along the south Texas coast as stations ran out of fuel, and there have been reports of inflated consumer prices in some Texan supermarkets.
Mr Trump is expected to visit Texas early next week.