A Yellowstone National Park visitor is presumed dead after a witness reported the visitor fell in to the Norris Geyser Basin.

According to YNP Public Affairs Officer Charissa Reid, a search was underway for the man who disappeared Tuesday afternoon.

Reid said the man is presumed dead because he has yet to be found.

“The recovery process is very difficult because of the hazards of the environment,” said Reid.

Reid said the man is in his 20s, but she would not identify the man or where he is from. He reportedly walked about 225 yards off the board walk before falling in to the hot spring.

The springs are known to reach temperatures that would be deadly to humans on contact.

“Norris Geyser Basin is the hottest and most changeable thermal area in Yellowstone,” according to the YNP website.

Norris Geyser Basin was closed following the incident.

Reid said she wanted to remind people of the danger of the springs and directed all visitors to the safety page on the YNP website.

Earlier this week, a 13-year-old boy and his father suffered thermal burns near the Castle Geyser.

They were flown to Salt Lake City for treatment.