This week in Texas, estimates put the number of people still missing from the Hill Country floods at 161, a daunting figure atop at least 120 deaths confirmed by authorities.

But that missing person tally might not be as precise as it seems.

Confusion and uncertainty can take hold after a shocking disaster and, despite best efforts by local authorities, it can be difficult to pin down how many people reported missing are actually unaccounted for. Some people on a list after California’s Camp Fire wildfire in 2018 were later found to be OK the whole time. The death count in the 2023 Maui fire was 102, far below the 1,100 people initially feared missing.

In Texas, several hundred people were reported missing to officials in Kerr County after the Fourth of July floods, said Freeman Martin, director of the Texas Department of Public Safety. Investigators whittled that number down to 161 by Tuesday after learning that some were counted twice and others were found alive.

“There’s nothing to celebrate about how well we’ve done this far, but there’s a lot of work to be done,” Martin said.

Authorities announced a phone number and email address for people to report missing friends or family.

“We need to keep an accurate count, as accurate as possible,” Jonathan Lamb of the Kerrville Police Department said in a plea to the public Wednesday. “So if you’ve reported somebody missing and they’ve been recovered safely, please let us know.”

The flooding sent walls of water through Hill Country in the middle of the night, killing at least 27 campers and counselors at Camp Mystic, a century-old all-girls Christian summer camp along the Guadalupe River. More remain missing from that camp and elsewhere.

The search in 88-degree Fahrenheit heat (31 degrees Celsius) has been made harder by overturned cars, trees, mud and other debris left in the wake of the ferocious flood.

“We will not stop until every missing person is accounted for,” Gov. Greg Abbott said. “Know this also: There very likely could be more added to that list.”

In 2017, more than 20 people died in the Tubbs fire in northern California. Sgt. Juan Valencia of the Sonoma County Sheriff’s Office recalled that most of the 100 people initially reported missing to his agency were found safe.

Working through a list of names in a disaster is both meticulous and time-consuming work, he said.

“Put yourself in a family member’s shoes,” Valencia said. “They’re concerned about their loved one. Are they really the victim of a disaster or did they maybe lose their cellphone? Basically you start calling temporary shelters, check family, friends. You check social media. That’s how we were able to get a lot of those.”

And he acknowledged that searching for victims of a water disaster poses distinct challenges.

“Sometimes you find them miles away,” Valencia said.

The 2018 Camp Fire in California ended up killing nearly 100 people, though the Butte County Sheriff’s Office had a list of 1,300 people unaccounted for at one point.

Abbott said Texas authorities were trying to learn more about people who were not registered at a camp or a hotel for the holiday and left no paper or digital trail in the region. He had a firm message for anyone contacting police about a missing person.

“If you make a prank call or provide false information, that’s a crime. … So you better be correct,” the governor said.