The first Atlantic hurricane of the year has slammed into southern Texas, bringing heavy rain, storm surges, and potentially life-threatening flash flooding.

Jame Rowles examines the damage after the docks at the marina where his boat was secured were destroyed as Hurricane Hanna made landfall, July 25, 2020, in Corpus Christi, Texas.
Jame Rowles examines the damage after the docks at the marina where his boat was secured were destroyed as Hurricane Hanna made landfall, July 25, 2020, in Corpus Christi, Texas. (AP)

Hurricane Hanna's winds have lashed the south Texas coast, knocking out power to thousands before it was downgraded to a tropical storm that still threatened flash flooding in the area already badly hit by Covid-19 infections.

Hanna came ashore on Padre Island on Saturday afternoon as a Category 1 hurricane on the five-step Saffir-Simpson scale, and later made a second landfall in Kenedy County, Texas on Sunday. 

More than 283,104 homes and businesses were without electricity by mid-morning, according to poweroutage.us. 

But some locals took advantage of the wild weather, with Alejandero Carcano, 16, and Jesse Garewal, 18, both residents of Galveston, surfing the high swells whipped up by Hanna.

READ MORE: Virus-weary Texas braces as Hurricane Hanna arrives

Local residents Alejandero Carcano, 16, and Jesse Garewal, 18, surf in high swells from Hurricane Hanna in Galveston, Texas, US, July 25, 2020.
Local residents Alejandero Carcano, 16, and Jesse Garewal, 18, surf in high swells from Hurricane Hanna in Galveston, Texas, US, July 25, 2020. (Reuters)

Hanna came nearly three years after Hurricane Harvey blew ashore northeast of Corpus Christi. 

Hanna was not expected to be as destructive as Harvey, which killed 68 people and caused an estimated $125 billion in damage in Texas.

READ MORE: Thousands flee Texas towns flooded by Harvey

Weakening as it headed west over land, Hanna was a tropical storm by Sunday morning, with its centre about 65 km from McAllen, Texas and about 105 km from Monterrey, Mexico, the US National Hurricane Center (NHC) said.

At 0400 CDT (0900 GMT), the storm's top sustained winds were around 95 kph, the centre said.

It was forecast to lose more steam as it moved across Texas and northeastern Mexico, and on Sunday weather watch officials cancelled the storm surge warning they had issued for the Texas coast.

Threat of flash flooding

"7 AM Radar update - Showers with heavy rain were developing from Victoria extending SE into the Gulf of Mexico, moving NW. Expect this trend to continue through mid morning," the National Weather Service Corpus Christi office said on Twitter.

Hanna still posed a threat, the hurricane centre said, noting it could dump upward of 45 cm of rain in the area through Monday.

"This rain will produce, life-threatening flash flooding, rapid rises on small streams, and isolated minor to moderate river flooding," the NHC said.

There were no immediate reports of casualties or widespread damage as the winds slowed to 80 mph once the storm headed inland, with further weakening expected overnight.

The Coast Guard helped rescue a couple without injuries after their sailboat began taking on water on Saturday evening in a harbour near Corpus Christi.

Area worst hit by Covid-19

Texas Governor Greg Abbott said on Saturday that the storm was especially challenging as it was sweeping through an area of the state that has been the worst hit by the coronavirus.

The Texas area struck by Hanna has struggled to contain outbreaks of Covid-19 in recent weeks. Cases along the state's coast have soared into the tens of thousands.

More than 400 people in Corpus Christi were hospitalised with the illness on Friday, according to city data.

The storm was not expected to affect offshore oil and gas production. Energy companies have not evacuated workers or shut down production from their Gulf of Mexico platforms because of Hanna.

READ MORE: 'Serious problem': US top expert warns as cases rise in largest states

Venezuela warns of heavy rains

Two other storm systems were churning on Saturday: Pacific Hurricane Douglas, bearing down on the Hawaiian islands, and Tropical Storm Gonzalo in the Atlantic, near the Windward Islands.

Douglas – at one point a powerful Category 4 hurricane – has weakened to a Category 1 storm with wind speeds of 90 miles per hour.

The NHC said on Saturday the storm "will be near the main Hawaiian Islands late tonight and will move over parts of the state Sunday and Monday," bringing high winds, heavy surf, and rainfall of up to 10 inches.

A hurricane warning was in effect in Oahu.

Meanwhile, Venezuela's government warned of heavy rains and gusting winds as Gonzalo moved west across the Caribbean.

Big waves have already started to pound the coast in eastern Venezuela and power was knocked out in some areas on Saturday, Venezuelan media reported.

Source: TRTWorld and agencies