At least two people have died as Hurricane Beryl slammed into southeast Texas, knocking out power for more than two million people while bringing heavy rain and fierce wind gusts.

When Beryl first hit Texas on Monday morning, it landed as a category one hurricane but has since been downgraded to a tropical storm.

Officials have warned of destructive winds, up to 15in (38cm) of rain and “life-threatening” storm surges.

More than 1,000 flights in Houston’s largest airport have been cancelled.

The state governor’s office has repeatedly urged residents not to underestimate the storm, which caused at least 10 deaths in the Caribbean days before.

In Texas, a 53-year-old man died after ripping winds downed powerlines and knocked a tree onto his home in Harris County, causing his roof to collapse.

In the same county, which includes parts of Houston, a 74-year-old woman was also reported dead after a tree crashed through the roof of her home. The police were notified by the woman’s granddaughter.

On Monday, police in one Houston suburb had already begun conducting water rescues as the hurricane continued to pound the state.

According to US forecaster AccuWeather, landfalling hurricanes of this kind are somewhat rare for Texas in July.

Sustained wind speeds in the Houston area had reached 75mph (120km/h) with wind gusts reaching 87mph (140km/h).

Torrential rainfall and flash flooding have also occurred in areas where inches of rain fell in just a few hours.

The storm is expected to lose strength as it gradually tracks north-northeast but flash flooding and heavy rain remains a risk.

More than 2.7 million customers in Texas are without power as of Monday afternoon, according to poweroutage.us.

At Bush Intercontinental Airport, Houston’s largest airport, 1,097 flights were cancelled, according to flightaware.com.

As the storm barrelled its way past Houston, tornado warnings were issued for dozens of other Texas counties in its path, including a few counties in Louisiana.

“Take cover now!” the National Weather Service warned in all caps in its weather update around 13:00 CDT (19:00 BST) for residents in Louisiana’s Northeastern Beauregard Parish.

“Move to an interior room on the lowest floor of a sturdy building. Avoid windows.”

Earlier, the city of Galveston, south-east of Houston, issued a voluntary evacuation order for some areas.

Storm surges in the Galveston area were predicted to reach 4-6ft above ground.

In Surfside Beach, police posted a photo of flood waters rising above the lower part of a truck’s door, feet above the ground.

The director of the US National Hurricane Center, Michael Brennan, has warned those living in Beryl’s path to find a safe place to be through Monday “as hazardous conditions will persist even after the centre of Beryl moves through”.

“There’s a very considerable risk of flash flooding across the Texas Gulf Coast, eastern Texas, ArkaTex [Arkansas-Texas] region.

“Do not ignore this very serious storm,” urged Acting Governor Dan Patrick.

The ports of Corpus Christi, Houston, Galveston, Freeport and Texas City have all closed, meaning there could be a temporary halt to exports.

All vessel movement and cargo operations have been restricted.

Refugio County, north of Galveston, on Saturday issued a mandatory evacuation – stating the limited capacity of emergency services staff, 4 July holiday traffic and the area’s weakened infrastructure from Hurricane Harvey in 2017 as reasons.

Nueces County, meanwhile, ordered the mandatory evacuation of visitors and strongly encouraged locals to leave as well.

More than 2,000 emergency responders have been made ready to deal with Beryl’s aftermath, Mr Patrick announced, including members of the Texas National Guard.

Beryl is expected to move east across America’s central states, including Mississippi, later in the week.

In the process, it will likely skip over central and west Texas, areas that are currently experiencing moderate to severe levels of drought.

Hurricane Beryl has been an unprecedented storm. At one stage, it became the earliest Category Five hurricane ever recorded.

It has already left a trail of devastation across the Caribbean – hitting islands including St Vincent and the Grenadines, Mayreau and Union, and Grenada especially hard.

The storm was also one of the most powerful to ever hit Jamaica and left hundreds of thousands of people without power.

Beryl brought heavy rain to the tourist hotspots of Cancún and Tulum in southern Mexico. No major damage was reported but the high winds felled trees and caused power outages.

While it is difficult to attribute specific storms to climate change as the causes are complex, exceptionally high sea surface temperatures are seen as a key reason why Hurricane Beryl has been so powerful.

It is the first hurricane of the 2024 Atlantic season but the US National Oceanic and Atmospheric Administration has warned that the North Atlantic could get as many as seven major hurricanes this year – up from an average of three in a season.