Hurricane Nicholas has made landfall on the Texas coast in the US, bringing heavy rain and the risk of life-threatening flooding.
The hurricane strengthened from a tropical storm late on Monday, before reaching land at 00:30 (05:30 GMT).
More than 280,000 power outages have already been reported in Texas, according to PowerOutage.us.
President Joe Biden declared an emergency in Louisiana and ordered federal assistance to the state.
It comes just weeks after Hurricane Ida – the fifth strongest to ever hit the US mainland – killed dozens and left more than a million Louisiana residents without power.
Nicholas is carrying maximum sustained winds of 75mph (120km/h), weather officials said, and is expected to hit the Houston area with up to 18 inches of rain.
The US National Hurricane Centre warned that “life-threatening flash flooding impacts, especially in highly urbanised metropolitan areas, are possible”, and the National Weather Service called it a “life-threatening situation”.
“We want to make sure that no one is caught off guard by this storm,” Louisiana Governor John Bel Edwards told a news conference.
He warned that drainage systems still clogged from Ida could trigger flash floods.
More than 119,000 homes and businesses remain without power in Louisiana due to Ida, he added.
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Texas Governor Greg Abbott declared states of emergency in 17 counties and three cities.
Houston Mayor Sylvester Turner warned of flooding and urged the city’s roughly 2.3 million residents to stay off streets and motorways.
“Take things seriously and prepare,” Mr Turner said at a news conference. “This is primarily a rain event and we don’t know how much rain we will be getting.”
Dozens of schools across the two states have been closed, and hundreds of flights have been canceled or delayed at airports in the Texas cities of Corpus Christi and Houston.