Tropical Storm Nicholas drenches US Gulf Coast

Region braces for 'life-threatening' flooding weeks after Ida

Tropical Storm Nicholas leaves roads damaged and flooded in Houston, Texas. AFP

Tropical Storm Nicholas moved slowly through the Gulf Coast on Tuesday, drenching Texas and Louisiana with torrential rain, flooding streets and leaving hundreds of thousands of homes and businesses without power.

No deaths have been reported from Nicholas, which weakened to a tropical depression on Tuesday evening, since it made landfall as a hurricane along the Texas Gulf Coast early on Tuesday, packing 121 km-per-hour winds.

It is the second major storm to threaten the region in recent weeks after Hurricane Ida killed more than two dozen people and left more than one million without power in Louisiana.

The storm is expected to progress slowly into Louisiana, Mississippi and the Florida panhandle through Thursday.

The storm could dump up to 51 centimetres of rain in parts of central and southern Louisiana, which may hinder restoration efforts.

By late afternoon more than 94,000 customers in Louisiana and 186,000 in Texas remained without power, according to a Reuters tally.

US President Joe Biden declared an emergency for Louisiana and ordered federal assistance for local responders due to the effects of Nicholas, the White House said.

Mr Biden has made the climate crisis one of his top priorities in recent weeks, having issued a “code red” on the recent extreme weather events across the US.

“Every part of the country, every part of the country is getting hit by extreme weather,” Mr Biden said last week at a briefing in New Jersey, which is reeling from the destruction caused by Ida.

Louisiana Governor John Bel Edwards declared a state of emergency on Sunday night before the storm made landfall, as the state is still recovering from Ida and last year's Hurricane Laura.

“The most severe threat to Louisiana is in the south-west portion of the state, where recovery from Hurricane Laura and the May flooding is ongoing,” Mr Edwards said.

Texas Governor Greg Abbott declared a state of emergency in 17 cities and three counties, and said rescue teams have been sent to the Houston area and along the coast to confront any flash flooding.

Houston Mayor Sylvester Turner said rainfall could overwhelm the city's streets and flood homes.

“This city is very resilient. We know what we need to do. We know about preparing,” Mr Turner said.

Houston suspended light rail and bus services on Monday, and hundreds of flights have been cancelled or delayed.

The city was devastated in 2017 when Harvey slammed into Texas as a Category 4 hurricane, unleashing up to 102 centimetres of rain and killing more than 100 people.

Though Nicholas is not expected to be anywhere near as destructive as Harvey, the National Weather Service forecasts rainfall of up to 41 centimetres in some parts of Texas.

Mr Turner urged Houston residents to stay off streets and highways. The National Weather Service called it a “life-threatening” situation.

Nicholas is the 14th named storm of the season, a number that typically is not reached until November.