Tropical Storm Beryl’s howling winds and torrential rain have killed at least three people, closed oil ports, grounded hundreds of flights and knocked out power to more than two million homes and businesses in southeast Texas.

Beryl, the season’s earliest category five hurricane on record, weakened from a hurricane after pounding the coastal Texas town of Matagorda with dangerous storm surges and heavy rain before moving across Houston, the US National Hurricane Center (NHC) said on Monday.

The storm, which was expected to rapidly weaken as it moved inland, swept a destructive path through Jamaica, Grenada and St Vincent and the Grenadines last week.

It has killed at least 12 people in the Caribbean and Texas.

In Texas, a 53-year-old man and a 74-year-old woman were killed in two incidents by trees that fell on their homes in the Houston area on Monday. A third person drowned, according to local officials.

The state’s energy industry, the country’s biggest producer of US oil and natural gas, braced for Beryl’s impact as the powerful storm slowed refining activity and prompted the evacuation of some production sites.

“Life-threatening storm surge and heavy rainfall is ongoing across portions of Texas. Damaging winds ongoing along the coast, with strong winds moving inland,” the NHC said even as Beryl began to lose strength.

Following warnings that it could be a deadly storm for communities in its path, residents had rushed to board up windows and stock up on fuel and other essential supplies.

Before daybreak, strong gusts and torrential rain lashed cities and towns such as Galveston, Sargent, Lake Jackson and Freeport, television footage showed.

By late morning, many fallen trees blocked roads in Houston as the worst of the storm passed, with persisting winds and some road flooding, rendering lanes on major freeways impassable.

The city barricaded flooded areas.

In video posted on social media by Houston’s local ABC station, crews using a life jacket and ladder fire truck rescued a man from a truck on a flooded stretch of freeway.

In a late morning press conference, Houston Mayor John Whitmire urged people to shelter in place.

He noted that flood waters exceeded 25cm across most of the city.c

The storm had strengthened into a category one hurricane as it crossed the warm waters of the Gulf of Mexico before making landfall.

But the NHC said it was expected to weaken rapidly as it moves across land, as hurricanes typically do, before becoming a tropical depression on Tuesday.

Beryl was expected to barrel over eastern parts of the state through the day before moving into the Lower Mississippi Valley and the Ohio Valley on Tuesday and Wednesday, the NHC said.

“People in the path of Beryl’s track should not let their guard down this week,” Accuweather said in a statement, warning of possible tornadoes as far away as Ohio and possible flash flooding as far north as Detroit.

US President Joe Biden is being regularly updated about the storm while administration officials remain in close contact with state and local counterparts, a White House official said.

More than two million homes and businesses in Texas have lost power, according to local utilities and PowerOutage.us data.

Several counties in southeastern Texas – including Houston, where many US energy companies are headquartered – are under a flash-flood warning as thunderstorms unleashed up to nearly 30cm of rain in some areas.