Yellowstone National Park officials on Wednesday (June 8) confirmed that a visitor has died after he tripped and fell into an acidic hot spring at the park.

Mr Colin Nathaniel Scott, 23, of Portland, Oregon, and his sister, Ms Sable Scott were on a visit to the park in Montana on Tuesday when they left the boardwalk in the Norris Geyser Basin and walked 206m. He then slipped and fell into a hot spring near Porkchop Geyser, park officials said.

His sister, who saw the accident, reported the fall, but by then nothing could be done.

Park rangers scouted the fragile crust of the geyser basin for Mr Scott's body but to no avail.

According to NBC News, efforts to recover his remains on Wednesday were stopped as there was nothing that could be safely recovered.

"They were able to recover a few personal effects," park spokesman Charissa Reid told Associated Press. "There were no remains left to recover."

The incident happened at one of Yellowstone's most volatile and hottest areas, where boiling water flows under a fragile rock crust, Daily Mail Online reported.

The water is said to be over 204 deg C in temperature, according to previous geological surveys.

Mr Scott, reported Jackson Hole Daily, graduated summa cum laude from Pacific University recently and was planning to pursue a doctorate programme in psychology in the fall.

"We extend our sympathy to the Scott family," park superintendent Dan Wenk said. "This tragic event must remind all of us to follow the regulations and stay on boardwalks when visiting Yellowstone's geyser basins."

Signs were placed to warn visitors to stay on boardwalks and trails in thermal areas to avoid dangers such as toxic gases, boiling pools and geysers, which are able to blast hundreds of feet into the air, according to The Telegraph.

Ms Reid explained that the crust can be as "thin as a skiff of ice".

Hot spring-related injuries in and around Yellowstone have claimed the lives of at least 22 people since 1890, said park officials.

Aside from at least two people who tried to swim in a hot spring, most of the deaths were accidents, according to park historian Lee Whittlesey, author of the book Death In Yellowstone.

On June 4, a 13-year-old boy was burned at Yellowstone when his father who was carrying him slipped into a hot spring.

According to The New York Times, the last recorded death was in August 2000 when Ms Sara Hulphers, 20, of Oroville, Washington, died in hospital after she fell into a hot spring and suffered third-degree burns.