Norris Geyser Basin in Yellowstone National Park, Wyo., in September 2009. (Beth Harpaz/AP)

Wyoming’s Norris Geyser Basin is the hottest thermal region in Yellowstone National Park. The geothermal activity 1,000 feet below the surface could cook a holiday roast: Scientists measured the highest temperature recorded in the park, 459 degrees, in the Norris thermal system. The surrounding habitat gets so warm that the Norris Basin is one of the few places in Yellowstone where sagebrush lizards can thrive. At the surface, the pools of acidic and super-hot water house living mats of green, orange and pink microorganisms.

Like many of the 840,000 people who visited Yellowstone in June, Colin and Sable Scott, a brother and sister from Oregon, came to marvel at the basin’s thermal features. But their visit took a turn for the horrific, as The Washington Post reported, when the pair left the protective boardwalk and hiked 225 yards into the basin.

“There’s a closure in place to keep people from doing that for their own safety and also to protect the resources because they are very fragile,” Lorant Veress, a Yellowstone deputy chief ranger, told NBC affiliate KULR 8 on Tuesday. “But, most importantly for the safety of people because it’s a very unforgiving environment.”

At the time, it was unclear exactly what went wrong next.

“Then, somehow, Colin Scott slipped, and as his sister watched, the 23-year-old tumbled into one of the boiling springs. Despite her immediate call for help and the prolonged search efforts by park staff, her brother was never seen again,” The Post reported in June. One of the few pieces of evidence left behind was a pair of Scott’s flip-flops.

A man visiting Yellowstone National Park died June 7 after he reportedly walked 225 yards away from the boardwalk and into an isolated area where he fell into a boiling hot spring. Authorities discuss their recovery efforts, which were halted on June 8. (East Idaho News)

A Freedom of Information Act filed by KULR 8 and released in November revealed the details of the accident. The pair had more than an unauthorized stroll in mind. Rather, their goal was to find a thermal pool and take a soak —  illegal conduct  that the park described as “hot-potting.”

Sable Scott took a video recording of her brother on her phone, the Associated Press reported, as he made his way toward a 4-foot-wide, 10-foot-deep pool. In the report obtained by KULR 8, Scott witnessed her brother as he “was reaching down to check the temperature of a hot spring when he slipped and fell into the pool.”

Though rangers were able to locate Scott’s body, bad weather impeded the immediate recovery attempt.

Later attempts would have been futile, due to the composition of the pool. “In a very short order, there was a significant amount of dissolving,” Veress told KULR.

This video captures a thermal lake in Yellowstone National Park, Wyo. (Newsflare)

Since 1870, the first recorded fatality in the park, 22 people have died in its thermal pools and geysers. Park historian Lee H. Whittlesey, writing in his 1995 book “Death in Yellowstone,” described another fatal incident of hot-potting. A 20-year-old lodge cook, joining other park employees for an illegal hot-pot party one late night in 1975, wound up in the wrong 179 degree-pool and died. 

Ranger Veress warned that straying beyond official paths and signs into Yellowstone is dangerous, as much of the park’s wilderness remains as untouched as possible.

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