Emergency officials in one East Texas county issued a stark warning to residents as the remnants of Hurricane Harvey doubled back toward land and dumped more rain on communities near the Texas-Louisiana state line.

The Facebook post from Tyler County Emergency Management warned residents of imminent and dangerous flooding.

"River levels will rise to near seventy nine feet. With additional rain fall accumulations, a potential elevation could reach near eighty two feet," the message said before ordering residents to leave the area.

"Anyone who chooses to not heed this directive cannont [sic] expect to be rescued and should write their social security [sic] numbers in permanent marker on their arm so their bodies can be identified. The loss of life and property is certain.

The message concluded, "GET OUT OR DIE!"

Just to the south of Tyler County, the city of Port Arthur found itself increasingly isolated as floodwaters swamped most major roads out of the city and spilled into a storm shelter with about 100 people inside. Motiva Enterprises closed its Port Arthur refinery, the largest in the nation, because of flooding.

Port Arthur Mayor Derrick Freeman posted on his Facebook page: "city is underwater right now but we are coming!" He urged residents to move to higher ground and avoid getting trapped in attics.

More than 500 people — along with dozens of dogs, cats, a lizard and a monkey — took shelter at the Max Bowl bowling alley in Port Arthur after firefighters popped the lock in the middle of the night, said the establishment's general manager, Jeff Tolliver.

"The monkey was a little surprising, but we're trying to help," he said.

Harvey initially came ashore as a Category 4 hurricane in Texas on Friday, then went back out to sea and lingered off the coast as a tropical storm for days, inundating flood-prone Houston.

Harvey's five straight days of rain totaled close to 52 inches, the heaviest tropical downpour ever recorded in the continental U.S.

The Associated Press contributed to this report.