A butte gave way at Badlands National Park, injuring five hikers/Larry McAfee, NPS, file photo of Yellow Mounds

A group of five hikers was injured at Badlands National Park in South Dakota when a butte they were standing on for a photograph gave way, dropping them six feet.

Park officials said the incident along the Door Trail occurred about 7 p.m. Saturday night. The five had hiked off trail and climbed up the butte to pose for a photo.

"Without warning, the harder rock surface they were perched on gave way to the softer rocks beneath. The family members, including four minors and one 18-year-old female, all sustained injuries," a park release said. "One patient was transported by Life Flight Helicopter to Rapid City Regional Hospital. Two others with less serious injuries were transported to the hospital by ambulance. Two had minor injuries that were treated on scene."

Badlands has received higher than average precipitation this spring. The soils and formations are primarily composed of soft clays, siltstones, and claystones. Rock layers that appear solid are very easily eroded and may become unstable when saturated, the park release said. Rain is a normal part of the erosion process that forms the park’s spectacular badland formations—and it can also weaken rock ledges and precipices.

“I want to urge all visitors to use extra caution when exploring the Badlands this year,” said Superintendent Eric Brunnemann. “Situations like this should remind us to dress appropriately with sturdy shoes and hiking gear."