Among the potential victims of the Hurricane Harvey are hundreds of thousands of undocumented immigrants who live in Houston and other hard-hit parts of Texas.

The storm is devastating the region just days before a new state law cracking down on sanctuary cities is scheduled to take effect. Advocates say it presents an entirely new set of challenges for a population already reeling from accelerated state and federal enforcement of immigration laws.

As the hurricane loomed, federal authorities and Texas Gov. Greg Abbott (R) said undocumented immigrants should seek shelter from the storm and rising floodwaters. In a joint statement, the U.S. Immigration and Customs Enforcement and U.S. Customs and Border Protection agencies said they would not target undocumented immigrants at evacuation sites, shelters or food banks, and would prioritize “lifesaving and life-sustaining activities” during the storm and its aftermath.

But Oscar Hernandez, a community organizer with United We Dream in Houston, said he knew of undocumented immigrants in the Houston area who were afraid to seek help from shelters and were bunking with neighbors instead. Others are worried about losing their houses or everything they own to floods.

“All of us are scared,” Hernandez said.

This drone video taken Aug. 27 shows the historic flooding in Houston caused by Hurricane Harvey. (ahmed.gul/Instagram)

Houston is the fourth-largest city in the United States and one of the most diverse. Its metropolitan area, which includes the city and surrounding suburbs, has the third-largest unauthorized immigrant population in the country, about 575,000 people, according to a report this year by the Pew Research Center. Unauthorized immigrants made up 8.7 percent of the metro area’s population as of 2014, more than double the national average.

Advocates say Texas’s looming crackdown on illegal immigration has already driven many of those immigrants further into the shadows, and possibly, out of the state.

On Friday, Texas will officially outlaw sanctuary cities, threatening local police chiefs with jail time and city officials with losing their jobs if they do not help deport immigrants. The new law is being challenged in court by Houston and a number of other cities and localities.

Texas is also leading a coalition of GOP officials in 10 states threatening to sue President Trump if he doesn’t act by Sept. 5 to start phasing out the Obama-era Deferred Action for Childhood Arrivals program, which has granted reprieves from deportation to nearly 800,000 undocumented immigrants.

Hernandez, who has DACA protection, said many immigrant families in Texas fear increased racial profiling, detentions and deportations in the state once the sanctuary law takes effect.

“As concerned as everyone is about the hurricane, we have another disaster that’s heading our way, led by the government, led by Trump,” said Hernandez, 29, who came to the United States from Puebla, Mexico, when he was 2 years old.

Eduardo Canales, director of the South Texas Human Rights Center, said the state is at risk of losing much-needed low-wage workers — cleaners, cooks, carpenters and landscapers — who because of the crackdown may not stick around to help Texas communities recover from the storm.

“People are leaving the state already. Who’s going to clean up the mess?” Canales said in a phone interview from his home in Corpus Christi. “All the landscaping, all the work that they do. All that service work . . . There’s going to be a lot of remodeling and a lot of work and somebody’s gotta do it.”

Ali Noorani, executive director of the National Immigration Forum, said Texas business and church leaders were already worried about losing workers before the hurricane struck.

“Things are really piling up for the immigrant community in Texas in a bad way,” Noorani said. “It’s hard to tell exactly how many people are going to be displaced, but I think already the Houston workforce is so immigrant-driven, that to rebuild the city of Houston is going to need the contributions of everybody.”

The undocumented workforce in Texas is 1.15 million. Of those, 32 percent work in hotels, restaurants and other service industries and 23 percent work in construction, according to Mark Hugo Lopez, director of Hispanic research at the Pew Research Center.