Trump closely monitoring Hurricane Harvey, readying emergency response

President Trump has made preparing an emergency repose to Hurricane Harvey at top priority, the White House said Friday, urging Americans in the path of the powerful storm to heed warning and instruction from local officials.

Tom Bossert, the president’s homeland security adviser, said Federal Emergency Management Agency resources were already in place in Texas and Louisiana.

“We encourage individual responsibility and planning, as always. And I would stress that this is a serious storm,” Mr. Bossert said.

With millions of people in the storms path, Harvey had maximum sustained winds of 110 mph, just shy of the benchmark for a Category 3 storm, according to the National Hurricane Center.

It was expected to continue gathering strength before coming ashore late Friday or early Saturday, with the potential to produce winds up to 125 mph and storm surges of 12 feet, the National Hurricane Center said.

Mr. Bossert dismissed reports that illegal immigrants would risk Immigration and Custom Enforcement action at emergency shelters in Texas.

“People shouldn’t be fearful of going to a shelter and receiving food and water. That isn’t a problem,” he said.

Mr. Trump headed to the presidential retreat in Camp David, Maryland, for the weekend. He will receive updates on the storm and have access to the same resources as at the White House, Mr. Bossert said.

“He is acutely focused on making sure that — and just the right thing, by the way — that the American people in the storm’s path have what they need,” he said.

Harvey grew quickly Thursday from a tropical depression into a Category 1 hurricane, and then to a Category 2 hurricane early Friday. The last Category 3 storm to hit the U.S. was Hurricane Wilma in October 2005 in Florida.

Superstorm Sandy, which pummeled New York and New Jersey in 2012, never had the high winds and had lost tropical status by the time it struck. But it was devastating without formally being called a major hurricane.

On Friday morning, the storm was about 115 miles southeast of Corpus Christi, moving 10 mph to the northwest.

All seven Texas counties on the coast from Corpus Christi to the western end of Galveston Island have ordered mandatory evacuations of tens of thousands of residents from all low-lying areas. Officials in four counties ordered full evacuations and warned there was no guarantee of rescue for people staying behind.

Voluntary evacuations have been urged for Corpus Christi and the Bolivar Peninsula, a sand spit near Galveston where many homes were washed away by the storm surge of Hurricane Ike in 2008.

Texas Gov. Greg Abbott has expressed concern that not as many people are evacuating compared with previous storms. He said Friday that there was still time for coastal residents to get out of Harvey’s path, but they must leave immediately.

The governor activated about 700 members of the state National Guard ahead of Harvey making landfall.

Harvey’s effect is expected to be broad: The hurricane center said large storm surges could be expected as far north as Morgan City, Louisiana, some 400 miles away from the anticipated landfall.

And once it comes ashore, the storm is expected to stall, dumping copious amounts of rain for days in areas such as flood-prone Houston, the nation’s fourth-most populous city, and San Antonio.

• This story is based in part on wire service reports.