Heavy rain and winds are lashing parts of Texas, which has taken a pounding from Category 4 Hurricane Harvey.

“Harvey continues to bring torrential rains and catastrophic flooding to south-east Texas,” the US National Weather Service says.

“The forward motion with Harvey has stalled. Due to this slow motion, another 15-25 inches (38-63cm) of rainfall is expected through to Thursday. Storm totals in some locations may approach 50 inches (127cm). This is producing devastating flooding.”

The storm made landfall on Friday night (Texas time), battering the Texas coast. It is the first major hurricane to make landfall on the US mainland since Wilma in 2005.

Harvey has now been downgraded to a Category 1 storm, but the damage is far from over.

“Coupled with its extremely slow movement and massive amounts of precipitation, the storm is expected to unleash catastrophic flooding in south-east Texas. Its greatest impact, however, may be yet to come,” catastrophe modeller AIR Worldwide says.

Federal Emergency Management Agency leader Brock Long says the US is preparing for a “years-long” recovery effort, and the immediate focus is on housing and flood insurance program policy.

“We’re setting up and gearing up for the next couple [of] years,” he told broadcaster CNN. “This disaster is going to be a landmark event.”