Two tourists are facing backlash after allegedly walking across fragile bacterial mats near the Grand Prismatic Spring in Yellowstone National Park, prompting concerns about both their safety and damage to the protected area.
According to the New York Post, Tanya Saueressig, a visitor from Livingston, Montana, recorded the incident over the weekend.
She said she was stunned as the pair walked away from the designated boardwalk and into the restricted area.
“I didn’t think it was real for a second… it was shocking,” Saueressig said.
She added that she feared the tourists could be seriously injured or fall through the ground.
The visitors reportedly walked across the delicate mats while taking selfies, eventually getting within about 50 feet of the spring's extremely hot water.
Saueressig said her concern turned to frustration as she watched the pair continue across the sensitive surface.
“They were totally oblivious to what was right under their feet. You’re causing so much damage with every step you take, and you don’t care,” she said.
The bacterial mats surrounding Yellowstone's hot springs play a major role in creating the vivid colors that make the geothermal features famous.
The mats can take about a year to grow back after being damaged, while a single footprint can destroy millions of cells.
The behavior also puts the tourists at serious risk.
Some geothermal waters in Yellowstone can reach temperatures of up to 180 degrees Fahrenheit, while the ground around hot springs may be thin and unstable.
Stepping onto the mats is considered “thermal trespassing” and can result in penalties that include fines, park bans and jail time.
Yellowstone visitors are required to remain on designated paths and are prohibited from touching, swimming in or soaking in the park's hot springs.
The incident is not the first time visitors have ignored those warnings.
In July 2025, a man wearing flip-flops reportedly entered a restricted area to retrieve hats that had blown onto the bacterial mats.
Yellowstone's geothermal features have also been the site of deadly accidents.
Safety officials have warned that severe burns and other injuries from entering or falling into hot springs have resulted in more than 20 deaths.