Sep 15, 2015 7:08 PM by NBC News
Authorities in Utah found four more bodies Tuesday in the aftermath of a flash flood described as a "wall of water" that swept away a van and an SUV near the Utah-Arizona state line Monday, bringing the death toll to 12.
Utah Emergency Management announced the discovery at around 2:25 p.m. local time (4:45 p.m. ET). One person is still missing.
"This hit with a vengeance we haven't seen for some time," said Kevin Barlow, the assistant fire chief in Hildale, Utah.
Barlow said that an SUV and a van carrying a total of 16 people had been swept away by the flooding on Monday evening. They were "hit by a large wall of water and debris," Washington County Emergency Services said in a statement.
Meanwhile, three people were found dead and four more were missing Tuesday after flash floods in a canyon in Zion National Park on Monday, the National Park Service said.
The group was canyoneering in Keyhole Canyon when storms dropped more than a half-inch of rain in an hour and caused floods, the park service said. Zion National Park is about a 40-mile drive north of Hildale.
The group in Hildale was swept away as they returned from a park Monday at around 5 p.m. local time (7 p.m. ET) when they found a canyon road — the only route out of the area — flooded, Hildale Mayor Philip Barlow said Tuesday. They got out and were watching the flooding on the blocked road, he said.
"Unbeknownst to them, a flash flood had developed up in the canyon and it came rushing down, and it actually came around behind the vehicles and engulfed the vehicles," the mayor said.
Three of the group were adults and the rest were children, ranging from 4 years old to teenagers, authorities said. Three children were rescued, officials said. One of those rescued spent the night in a hospital but was scheduled to be released Tuesday.
Earlier Tuesday, when nine bodies had been found, officials said three children and one adult remained missing; emergency management did not say whether the three found after that announcement included an adult or whether all were children.
The floods came after heavy rains fell in the canyons just north of Hildale and its sister town of Colorado City, Arizona, sending waves of water barreling through the streets. They sit at the foot of picturesque red rock cliffs about 315 miles south of Salt Lake City.
Hildale resident Guy Timpson told NBC News that searchers were were trying to sort through "a mass of debris."
"We've got quite an effort going on," he said. "It's been pretty amazing to see the community coming together to do what they can."
More than 600 emergency responders and volunteers were involved in the search and recovery effort Tuesday, Washington County Sheriff Cory C. Pulsipher said. The governor authorized the National Guard to be mobilized to help, Lt. Gov. Spencer Cox said.
Ted Barlow, who lives in Colorado City, described the storm as among the worst in decades.
The downpour lasted for about 20 to 30 minutes and brought rapid and intense flooding from nearby mountains.
"Everyone is family here, and it's a tragedy however you look at it," Barlow said.
The National Weather Service had issued a flash flood warning earlier in the day, leading nearby Zion National Park to close all slot canyons as a precaution.
More thunderstorms are predicted for Tuesday with up to half-an-inch of rainfall predicted, according to Weather Channel senior forecaster Kevin Roth.
"If that hits all at once it could be bad," he said. "But even if it doesn't hit them directly and ends up in the mountains they could still be affected."
Hildale served as a home base for polygamous sect leader Warren Jeffs.
Members of the sect, whose members believe polygamy brings exaltation in heaven, are believed to be discouraged from watching TV, using the Internet or having much contact with the outside world.
More than four years after Jeffs was sentenced to life in prison for sexually assaulting underage girls he considered brides, the community is split between loyalists who still believe Jeffs is a victim of religious persecution and defectors who are embracing government efforts to pull the town into modern society.
The community is a patchwork of upscale, elegant residences surrounded by large walls and unfinished, dilapidated houses that remain just as they were in the early 2000s, when Jeffs ordered that all construction stop in Utah to focus on building his compound in Texas.