At least 27 children and counselors from a beloved all-girls summer camp in central Texas have died in the devastating flash floods that tore across central Texas, the camp said in a statement Monday, as a frantic search for those still missing enters its fourth day.

“Our hearts are broken alongside our families that are enduring this unimaginable tragedy,” the private Christian camp, Camp Mystic, said in a statement on its website. “We are praying for them constantly.”

It’s unclear how many of the 27 fatal victims were children and how many were counselors. Across the state, at least 81 people have died in the flooding since Friday, officials said.

On Sunday, local authorities in Kerr County, where the worst of the flooding occurred, said 10 children and a counselor were among the many people still missing. It’s unclear if that number had changed.

“We have been in communication with local and state authorities who are tirelessly deploying extensive resources to search for our missing girls,” the statement said.

There were about 700 children at the camp when relentless rain caused the nearby Guadalupe River to surge over 26 feet in less than an hour on Friday, said Texas Lt. Gov. Dan Patrick. Photos taken at the scene show a building where some of the children slept with broken windows and a blown-out wall. Among the debris-covered mud were pink blankets and stuffed animals.

“We will remain 100% dedicated, searching for every single one of the children who were at Camp Mystic as well as anybody else in the entire riverbed,” Texas Gov. Greg Abbot vowed at a news conference Sunday. “We are working as swiftly as possible.”

Warnings for deadly Texas flash flooding came with little time to act

For the meteorologists and hydrologists tracking the weather patterns that led to the deadly floods across Texas Hill Country, the most urgent advisories weren’t deployed until it was almost too late, according to interviews and advisories.

Forecasters said they pushed out warnings as fast as they got the data. But the hilly terrain and the trickiness of predicting flash floods made forecasting and alerting communities along the Guadalupe River in real time particularly challenging.

“This is a problem that we are constantly trying to work on: how to better communicate,” Greg Waller, a hydrologist at the National Weather Service’s West Gulf River Forecast Center in Fort Worth, told USA TODAY. “We can issue the best forecast in the world, but if it’s not put in the hands of the individuals so they can make the best decision, that forecast has little value.”

Read more: Warnings for deadly Texas flash flooding came with little time to act

– Rick Jervis

Guadalupe River rose nearly 30 feet in less than an hour

Flood watch in effect across central Texas as rescues continue

The National Weather Service extended a flood watch through 7 p.m. local time as downpours were expected through Monday, including in hard-hit parts of the state.

Federal forecasters said it’s difficult to pinpoint exact locations where the heaviest rain will fall, noting that an uptick in intensity is possible over the Hill Country, where the worst of deadly floods have occurred.

Widespread rainfall amounts of 2 to 4 inches were expected, forecasters said, warning that some areas could receive 10 inches of rain.

“The thunderstorms should become more organized and move westward possibly across the flood-ravaged portion of Texas during the day today,” the weather service said Monday.

Trump plans to visit Texas after deadly floods

Trump said he expects to visit Texas later this week after catastrophic flooding caused extensive death and destruction in the state.

“Probably on Friday,” Trump told reporters on Sunday when asked about visiting the state. “We wanted to leave a little time. I would’ve done it today, but we’d just be in their way.”

Earlier on Sunday, Trump signed a major disaster declaration for hard-hit Kerr County, unlocking federal funding for first responders on the ground and offering FEMA assistance to victims of the flooding.

— Zac Anderson