Tropical Storm Nicholas threatens to swamp Texas coast

Tropical Storm Nicholas gained strength as it tracked up the Texas coast hours before its expected landfall late Monday, threatening to unleash a dangerous deluge of rainfall on the southern US state, meteorologists warned.

At 2100 GMT Nicholas was located some 70 miles (115 kilometers) south of Port O'Connor on the Gulf of Mexico, with Texas's largest city of Houston squarely in the storm's sights, according to the National Hurricane Center.

Packing maximum winds of 65 miles per hour, Nicholas was forecast to bring "life-threatening" flash flooding and storm surges when it barrels ashore, the Miami-based NHC said.

"Nicholas could be near hurricane strength when it reaches the central Texas coast," it added, with the storm's center due to move onshore Monday night.

Between six and 12 inches (15-30 centimeters) of total rainfall is expected to wallop parts of Texas and western Louisiana, with isolated maximum amounts of 18 inches.

"This rainfall may produce areas of considerable flash and urban flooding," the center said.

Texas Governor Greg Abbott urged state residents to comply with warnings and directions from local authorities.

Sylvester Turner, the mayor of Houston, parts of which were devastated by Hurricane Harvey in 2017, said the city was on high alert.

Authorities have erected barricades, activated Houston's office of emergency management and told residents to take extra safety precautions.

"I urge everyone to be OFF the roads by sun down and to avoid driving tonight through tomorrow as we anticipate heavy rainfall," Turner posted on Twitter.

The Lone Star State is no stranger to hurricanes, but scientists warn that climate change is making the storms more powerful, posing an increasing risk to coastal communities.

Coastlines are already suffering from flooding, which has been amplified by rising sea levels.