Hurricane Harvey, slowing to a Category 1 storm, moved farther inland Saturday, but forecasters warned that it continues to deliver life-threatening storm surges up to 12 feet in some areas and the danger of "catastrophic" flooding from torrential rains across the middle and upper Texas coast for several days.

At 6.a.m.CDT, the National Hurricane Center clocked Harvey's sustained wins at 85 mph, dropping it from a Category 2 storm to a Category 1 and said it would likely slow to a Tropical Storm later in the day. It was 30 miles southwest of Victoria, moving northwest at 6 mph.

President Trump tweeted Saturday morning he was closely monitoring the hurricane, "leaving nothing to chance."

Although no longer a powerful Category 4 storm, Harvey is far from a spent force. The National Weather Service says Harvey is expected to stall and spin for the next three to five days, delivering heavy rainfall for the next three days. It could also slip back into the Gulf and regenerate as a powerful storm and head up the coast toward Louisiana.

A flash flood watch remains in effect across southern Texas until Tuesday evening, as Harvey is expected to stall and spin for the next three to five days, drenching parts of the middle and upper Texas coast through Wednesday. Forecasters predict as much as 40 inches of rain in some areas.

Harvey "may be nothing short of a flooding disaster," for Texas, according to AccuWeather meteorologist Alex Sosnowski, who said some communities could be underwater for days. Forecasters were already measuring 28-foot-high waves near the eye of the storm.

Cities are assessing hurricane damage, and there have been some reports of injuries.

More: Here's how to help victims of Hurricane Harvey

According to The Associated Press, Rockport, a coastal city of about 10,000 people, was directly hit when Harvey came ashore.

Rockport City Manager Kevin Carruth told KIII-TV that multiple people were taken to the county’s jail for assessment and treatment after the roof of a senior housing complex collapsed. Carruth also said that the historic downtown area has also sustained heavy damage, according to KIII-TV.

As of late Friday night, at least 10 people were treated for injuries, KIII-TV reported.

Corpus Christi police said a homeowner shot an intruder after Hurricane Harvey made landfall. The victim was "coherent" when he was rushed to a hospital, police say.

As of early Saturday morning, the Electric Reliability Council of Texas said in a statement that more than 211,000 consumers were without power along the Gulf Coast, with more than 100 circuits currently out of service.

Harvey is the first major hurricane — classified as Category 3 or above — to hit the U.S. since Hurricane Wilma in 2005. Harvey gradually weakened after hitting the coastal cities, with the National Hurricane Center downgrading it to a Category 2 storm though it still sustained 110-mph winds.

More: Hurricane Harvey smacks Texas: What we know now

Late Friday, federal authorities granted Texas Gov. Greg Abbott's State of Disaster request for 700 National Guard members in 30 counties to help with emergency disaster relief associated with the expected damage from Harvey.

He warned of record-setting flooding in multiple regions of the state and urged people to get out of harm's way. “You don’t want to put yourself in a situation where you could be subject to a search and rescue.”

Kirsten Crow, Rick Jervis, Doug Stanglin and Doyle Rice of the USA TODAY NETWORK contributed to this report.