Deadly 2015 Utah flooding swept away families in small town, hikers in Zion National Park

Name: Remembering Utah's deadliest natural disaster
Uploaded: 2022-09-14T14:04:29-04:00
Duration: 1 min 3 s
Description: Strong thunderstorms moved through southwestern Utah on Sept. 14, 2015, creating deadly flash flooding in Hildale, Utah, and Zion National Park that would claim the lives of 20 people.

Remembering Utah's deadliest natural disaster

Strong thunderstorms moved through southwestern Utah on Sept. 14, 2015, creating deadly flash flooding in Hildale, Utah, and Zion National Park that would claim the lives of 20 people.

Multiple strong thunderstorms with heavy rainfall moved through southwestern Utah on Sept. 14, 2015, creating significant and deadly flash flooding in Hildale, Utah, and Zion National Park that would claim the lives of 20 people, including 10 children.

The two flash flooding events in the small polygamist community along the Utah-Arizona border and in one of the nation's famous national parks remain Utah's deadliest natural disasters. One death was also reported south of the border with Arizona.

Flash flooding occurs when heavy rainfall, usually over a long period, moves over a dry land area. When water exceeds the ability of the ground to absorb it, flash flooding occurs.

According to the National Weather Service's Salt Lake City office, heavy rainfall began in the early afternoon of Sept. 14, causing flash flooding in Short Creek in Hildale and then flooding Highway 59.

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A second strong thunderstorm again moved over Hildale, causing more flooding. According to the NWS summary, 16 people were waiting for the flooding to subside and sought shelter in two vans when a large flood swept the vehicles down a channel.

People take pictures and watch as construction equipment removes flood debris from Short Creek as it crosses Central Street on September 15, 2015 in Colorado City, Arizona. Flash floods from heavy rains on the afternoon of September 14, 2015 washed away two cars in Hildale as they were crossing a flooded creek, killing 13 people. (Photo by George Frey/Getty Images) ( )

Personnel from the Mohave County Sheriffs Search and Rescue search Short Creek for missing bodies on September 15, 2015 in Colorado City, Arizona. Flash floods from heavy rains on the afternoon of September 14, 2015 washed away two cars in Hildale as they were crossing a flooded creek. (Photo by George Frey/Getty Images) ( )

The twisted wreckage of two vans that were washed away in a flash flood with women and children inside rest on the bank of Short Creek on September 15, 2015 in Hildale, Utah. Flash Floods from heavy rains on the afternoon of September 14, 2015 washed away two vans in Hildale as they were crossing a flooded creek, killing 13 people. (Photo by George Frey/Getty Images) ( )

Onlookers watch as construction equipment removes flood debris from Short Creek as it crosses Central Street on September 15, 2015 in Colorado City, Arizona. Flash Floods from heavy rains on the afternoon of September 14, 2015 washed away two cars in Hildale as they were crossing a flooded creek, killing 13 people. (Photo by George Frey/Getty Images) ( )

With a searcher in the background, local residents walk along the edge of Short Creek where two vans were swept away the day before on September 15, 2015 in Colorado City, Arizona. Flash floods from heavy rains on the afternoon of September 14, 2015 washed away two cars in Hildale as they were crossing a flooded creek, killing 13 people. (Photo by George Frey/Getty Images) ( )

Two woman walk amongst debris left behind after a flash flood on September 15, 2015 in Hildale, Utah. Flash floods from heavy rains on the afternoon of September 14, 2015 washed away two cars in Hildale as they were crossing a flooded creek, killing 13 people. (Photo by George Frey/Getty Images) ( )

A car sits on the side of the road after being pulled from Short Creek as woman and rescuers watch large construction equipment remove flood debris from Short Creek as it crosses Central Street on September 15, 2015 in Hildale, Utah. Flash Floods from heavy rains on the afternoon of September 14, 2015 washed away two cars in Hildale as they were crossing a flooded creek, killing 13 people. (Photo by George Frey/Getty Images) ( )

A gate closes the road as it crosses Short Creek on Hildale Street on September 15, 2015 in Hildale, Utah. Flash Floods from heavy rains on the afternoon of September 14, 2015 washed away two cars in Hildale as they were crossing a flooded creek, killing 13 people. (Photo by George Frey/Getty Images) ( )

A baby seat sits in front of half of one of two vans that were washed away in a flash flood with women and children inside rest on the bank of Short Creek on September 15, 2015 in Hildale, Utah. Flash Floods from heavy rains on the afternoon of September 14, 2015 washed away two vans in Hildale as they were crossing a flooded creek, killing 13 people. (Photo by George Frey/Getty Images) ( )

The twisted wreckage of one of two vans that were washed away in a flash flood with women and children inside rest on the bank of Short Creek on September 15, 2015 in Hildale, Utah. Flash Floods from heavy rains on the afternoon of September 14, 2015 washed away two vans in Hildale as they were crossing a flooded creek, killing 13 people. (Photo by George Frey/Getty Images) ( )

After the floodwaters receded, the mud-covered and warped vehicles were found mangled in the flooding debris but without the people inside. Photos in the aftermath show search efforts in Colorado City, Arizona, and Hildale.

After an extensive search, local authorities said three people swept away were rescued, and 13 people inside those vehicles died. According to the NWS summary of the deadly flooding event, the victims included three women ages 27, 28 and 30. The remaining victims were all children; the youngest was just 4 years old.

Hiking group overcome by floodwaters in slot canyon

Water flows down Pine Creek in Zion's National Park, a possible location where lost hikers might be on September 15, 2015 in Springdale, Utah. Seven hikers died after a flash flood that also killed 13 women and children in two vans that were swept away by the flood waters. (Photo by George Frey/Getty Images) (Getty Images)

On the same day just one hour north of Hildale, a hiking group was lost when strong storms triggered flash flooding in Zion National Park. The water quickly overtook the slot canyon the group was exploring. Seven hikers between 51 and 59 years old were killed in the flash flood.

On the morning of Sept. 14, the NWS office in Salt Lake City issued a moderate risk of flash flooding, including a higher risk for flash flooding in slot canyons that Zion is known for.

The Los Angeles Times reports the hikers were all experienced with canyoneering training when they descended into Keyhole Canyon. According to the NWS, flooding in Keyhole Canyon happened quickly, and no one could reach higher ground.

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In addition to the deadly cost of the flooding, the NWS estimated $750,000 in property damage to Washington County, Utah, as the water damaged roads, power lines and bridges. Flooding destroyed multiple cars, and homes were damaged during the floods.

Flash flooding remains the second-deadliest type of extreme weather in the U.S., killing more people yearly than hurricanes, tornadoes and lightning. Only heat is deadlier than flash floods.

Heat kills more people in an average year than any other type of extreme weather. (FOX Weather)