KERRVILLE, Texas — The death toll from the July Fourth flash flood that ravaged a swath of central Texas Hill Country rose on Tuesday to at least 109, many of them children, as search teams pressed on through mounds of mud-encrusted debris looking for scores of people still missing.

According to figures released by Governor Greg Abbott, authorities were seeking more than 180 people whose fate remained unknown four days after one of the deadliest US flood events in decades.

The bulk of fatalities and the search for additional victims were concentrated in Kerr County and the county seat of Kerrville, a town of 25,000 residents transformed into a disaster zone when torrential rains struck the region early last Friday, flooding the Guadalupe River basin.

The bodies of 94 flood victims, about a third of them children, have been recovered in Kerr County alone as of Tuesday, Texas Mr. Abbott said at a late-afternoon news conference after touring the area by air.

The Kerr County dead include 27 campers and counselors from Camp Mystic, a nearly century-old all-girls Christian summer retreat on the banks of the Guadalupe near the town of Hunt. The camp director also perished.

Five girls and a camp counselor were still unaccounted for on Tuesday, Mr. Abbott said, along with another child not associated with the camp.

As of Tuesday, 15 other flood-related fatalities had been confirmed across a swath of Texas Hill Country known as “flash flood alley,” the governor said, bringing the overall tally of lives lost to 109. Reports from local sheriffs and media have put the number of flood deaths outside Kerr County at 22.

But authorities have said they were bracing for the death toll to climb as flood waters recede and the search for more victims gains momentum.

Law enforcement agencies have compiled a list of 161 people “known to be missing” in Kerr County alone, Mr. Abbott said. The roster was checked against those who might be out of touch with loved ones or neighbors because they were away on vacation or out of town, according to the governor.

‘FIND EVERY SINGLE PERSON’
He said another 12 people were missing elsewhere across the flood zone as a whole, a sprawling area northwest of San Antonio.

“We need to find every single person who is missing. That’s job number one,” Mr. Abbott said.

On Tuesday, San Antonio-born country singer Pat Green disclosed on social media that his younger brother and sister-in-law and two of their children were among those “swept away in the Kerrville flood.”

Hindered by intermittent thunderstorms and showers, rescue teams from federal agencies, neighboring states and Mexico have joined local efforts to search for missing victims, though hopes of finding more survivors faded as time passed. The last victim found alive in Kerr County was last Friday.

“The work is extremely treacherous and time-consuming,” Lieutenant Colonel Ben Baker of the Texas Game Wardens said at a press conference. “It’s dirty work. The water is still there.”

A water-soaked family photo album was among the personal belongings found in flood debris by Sandi Gilmer, 46, a US Army veteran and certified chaplain volunteering in the search operation along the Guadalupe at Hunt.

“I don’t know how many people in this album are alive or deceased,” she said, flipping through images of two toddlers and a gray-haired man. “I didn’t have the heart to step over it without picking it up and hoping to return it to a family member.”

MAKINGS OF A DISASTER
More than a foot of rain fell in the region in less than an hour before dawn last Friday, sending a wall of water cascading down the Guadalupe that killed dozens of people and left mangled piles of debris, uprooted trees and overturned vehicles.

Public officials have faced days of questions about whether they could have alerted people in flood-prone areas sooner.

The state emergency management agency warned last Thursday, on the eve of the disaster, that parts of central Texas faced a flash floods threat, based on National Weather Service forecasts.

But twice as much rain as predicted ended up falling over two branches of the Guadalupe just upstream of the fork where they converge, sending all that water racing into the single river channel where it slices through Kerrville, City Manager Dalton Rice said.

Mr. Rice has said the outcome was unforeseen and unfolded in a matter of two hours, leaving too little time to conduct a precautionary mass evacuation without the risk of placing more people in harm’s way.

Scientists have said extreme flood events are becoming more common as climate change creates warmer, wetter weather patterns in Texas and other parts of the country.

At an earlier news briefing on Tuesday, Kerr County Sheriff Larry Leitha rebuffed questions about the county’s emergency operations and preparedness and declined to say who was ultimately in charge of monitoring weather alerts and issuing flood warnings or evacuation orders.

He said his office began receiving emergency-911 calls between 4 a.m. and 5 a.m. on Friday, several hours after the local National Weather Service station issued a flash-flood alert. “We’re in the process of trying to put (together) a timeline,” Mr. Leitha said.

Mr. Abbott said a special session of the Texas legislature would convene later this month to investigate the emergency response and provide funding for disaster relief. — Reuters