A man was seen falling into a hot spring at Yellowstone National Park Tuesday and searchers are treating the case as a probable fatality, the park said.
A witness reported that a man in his early 20s walked off a boardwalk and into a hot spring in the Norris Geyser Basin. A body had not been found as of Tuesday evening, the park’s office of strategic communications said in a statement.

Searchers were using "extreme caution" given the hazardous nature of the area, which contains the park’s hottest thermal springs. Many of the hot springs in the basin maintain temperatures at or above 199 degrees, according to the park’s website.
The area where the man reportedly fell into the hot springs is about 225 yards off of the boardwalk, the park said in a statement.
The possible fatality at Yellowstone comes on the heels of recent high-profile incidents at at the park.
On May 9, two tourists put a baby bison into the back of their vehicle and drove it to a ranger station, believing the animal was cold. The animal was later euthanized after the herd rejected it and the abandoned animal kept approaching people and cars, the park service said.
On May 14, a group of Canadian tourists left the boardwalk near the Grand Prismatic Spring and tramped around the environmentally protected and dangerous area, taking photos and videos which were then posted online.
Three men, who posted the videos on a Facebook page titled "High on Life SundayFundayz" were charged with federal counts, according to court documents. The group posted an apology online and said they were overzealous, and also pledged to donate $5,000 to Yellowstone.