An Indiana mother and father are alerting people about an overlooked danger after the tragic loss of their two young children last year.

On April 23, 2022, Crystal and Brian Clark, along with their son Xander, 9 and daughter, Ziva, 8, went out to Indian Oaks, a nearby campground that the family frequently visited.

It had been fairly windy that day but the sun was shining, Crystal Clark told Fox News Digital.

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"I decided after [lunch] we should go for a golf cart ride because it was a beautiful day," Crystal Clark added.

After seeing some friends go for a ride, the Clarks decided to do the same and meet up at their favorite fishing spot.

crystal and brian clark with kids

Crystal and Brian Clark, shown with their two kids, Xander (bottom left) and Ziva (middle), are spreading awareness about the importance of getting trees checked after the children's unexpected deaths at a campground in Indiana on April 23, 2022. (Crystal Clark)

"Ziva was taking their fish off [the line] 'cause that was one of her favorites things to do, and then she'd kiss it and then she'd toss it back in the water," said Crystal Clark.

"She loved everything," she added. 

"She loved every animal, fish or not."

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Xander was very excited to go fishing that day, but the family decided to instead go for one more ride on the golf cart, with the parents in the front and the kids in the back, before settling down to fish.

xander and ziva piggyback ride

Xander, 9, and Ziva, 8, were riding on a golf cart with their parents when a tree fell and the branches landed on them. (Crystal Clark)

"The trails are always open. People drive their cars to get to their campers, so it's not like it was in a rural area that wasn't used often," Crystal Clark noted.

The family had decided to make their way back when the parents heard a loud noise.

"It was so loud, you didn't know which direction it was coming," Crystal Clark recalled.

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"We didn't know until it was too late."

A tree had collapsed onto a Ford F-150 and the branches fell on top of the Clarks' golf cart, which then rolled off the roof, hitting their children in the back — less than six inches behind their parents.

clark family at game

Crystal and Brian Clark decided to put up a billboard in an effort to warn families and prevent the tragedy from happening to anyone else. (Crystal Clark)

Both children were pronounced dead at the scene, FOX 59 in Indianapolis reported at the time.

After their children's deaths, it took the Clarks about seven weeks to return to their family's beloved campsite. 

Yet while there, Crystal Clark shared a "crazy idea" with her husband that she said she'd been thinking about for a while.

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"What do you think about doing a billboard with the kids on it to try and spread awareness to save another life?" Crystal Clark said she told her husband.

"You worry about your children falling out of a tree. You don't worry about a tree falling on them."

Brian Clark did not think it was "crazy" at all.

Crystal Clark said that in October, she reached out to a company about advertising on a billboard, but she had a difficult time at her first go.

She then took to her own Facebook page to spread awareness about the necessity of checking trees after a storm or windy day.

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"Today is a windy day. Please check your trees. Please be aware, you could save a life," she wrote on Facebook.

xander and ziva smiling

"[Xander and Ziva] were a good balance of each other," Brian Clark told Fox News Digital about his children. (Crystal Clark)

"The next thing I know, I get a contact from Lamar billboards," Crystal Clark said.

The company "heard what happened," she said, "and were very much wanting to help us."

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On the week of March 6, 2023, Lamar Advertising installed the Clarks' billboard.

xander and ziva clark billboard

With the help of Lamar Advertising, Crystal and Brian Clark put up a billboard to urgently warn others about the dangers of falling trees. (Crystal Clark)

It reads: "Check your trees! After Storms, Heavy Rains and Windy Days. You would save a life! Xander and Ziva Clark — killed by a falling tree 4/23/2022."

"I bawled by eyes out at just helpful they have been," Crystal Clark said of the company.

After the first billboard went up, Lamar put up nine digital billboards across central Indiana, without telling the Clarks and without asking for any additional fee — but simply "out of the kindness of their heart," Crystal Clark said.

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The Clarks are now focused on spreading their warning in the hope that "nobody else has to deal with what we are dealing with," Brian Clark told Fox News Digital.

"[The] bottom line is just to get somebody to think and check something before, you know, it happens to them, too."

— Brian Clark

"Crystal says it all the time, 'You worry about your children falling out of a tree. You don't worry about a tree falling on them,'" he said. 

While falling trees may appear to be a "freak accident," they're not as rare as people think, the Clarks said.

Through their outreach, the couple said, they've heard from people who have found themselves in similar situations.

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"It's just something that you don't think about … [The] bottom line is just to get somebody to think and check something before, you know, it happens to them, too," said Brian Clark.

clark family halloween

Crystal and Brian Clark are seen in Halloween costumes with their late children, Ziva (front left) and Xander (front right). (Crystal Clark)

Bert Cregg, a professor in the Department of Horticulture at the Michigan State University College of Agriculture & Natural Resources, wrote in an online article, "Damaged trees and hanging tree limbs are extremely dangerous. Trees that are damaged in storms often have decay or other hidden defects and can drop without warning."

In addition, various types of damage can occur to trees "from violent weather," according to Lindsey Purcell, an urban forestry specialist at Purdue University's Department of Forestry & Natural Resources.

"All parts of the tree should be inspected during a post-storm assessment," Purcell noted in an informational online brochure about trees and storms.

crystal clark with xander and ziva

The Clark family would regularly go out to Indian Oaks campsite because the kids loved playing outside. (Crystal Clark)

The unimaginable may have happened at Indian Oaks, but that place will always be full of fond memories of the kids, the Clarks noted.

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"Of the three years that we were out there, that was probably the most our children grew," Brian Clark said. "Being away from computers, and games and TVs … Our kids got that freedom to be able to be outside and do things that not everyone gets to do on a regular basis."

The children both loved the outdoors and were very active, their parents said.

Rain or shine, their son Xander could be found shooting hoops, even if it meant he was "slipping and sliding all over the porch," Brian Clark said. 

ziva solo shot

Their daughter Ziva, "the firecracker," loved gymnastics and hoped to make it to the Olympics one day. (Crystal Clark)

Daughter Ziva was a competitive gymnast with aspirations of going to the Summer Olympics, and if that did not work out she would try and go for the Winter Olympics and be a professional snowboarder, Brian Clark said with a laugh.

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Xander, a third grader, loved science and math and dreamed of being a scientist.

xander solo shot

Xander, a third grader, loved playing basketball and dreamed of being a scientist one day. (Crystal Clark)

"Xander was always the one asking all the questions. He always loved to learn," Brian Clark said.

Ziva was known as the "firecracker" of the two.

The second-grader enjoyed serving as the "assistant" at school by helping her classmates with projects, or being the first one to volunteer to bring a friend to see the nurse, Crystal Clark said. 

"She would draw out his fun and he would reel her in and teach her things as well."

— Brian Clark about his late children

As brother and sister, the kids were the perfect pair and "were a good balance" of each other, Brian Clark said.

"She would draw out his fun, and he would reel her in and teach her things as well," he added.

Crystal Clark said she has been amazed by the outreach and the responses the family has received to their story.

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While they'll continue to raise awareness, the parents have found this time of healing to be very emotionally and physically draining, they said.

billboard split

Crystal and Brian Clark hope they can save a life by sharing their own heartbreaking story of losing their children from a falling tree accident. (Crystal Clark)

"You think it would be easy because we are talking about our kids, but it's also because we've lost them [that it] hurts," Crystal Clark said. 

"We want to talk about them but the grief of it's just really hard."

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The Clarks hope the billboards are working and that their message is preventing something like this from happening to anyone else.

"We really could have just saved a life by putting this out there," said Crystal Clark.