[Updated 9:30 p.m. ET] Three Yosemite National Park tourists are presumed dead after climbing over a guardrail into the Merced River, park officials said Wednesday.
"So far we have seen no clues or no evidence of any of the bodies," said Kari Cobb, a spokeswoman for Yosemite National Park. "We are presuming that all three of them are dead ... we will scale up the search once the water levels have receded and we can insert crews to look for the bodies in the river safely."
Ramina Badal, 21, and Hormiz David, 22, both of Modesto, California; and Ninos Yacoub, 27, of Turlock, California, had hiked the popular Mist Trail to the top of Vernal Fall at about 1:30 p.m. Tuesday.
Vernal Fall is 317 feet high. The Mist Trail is the most popular trail in Yosemite National Park and attracts between 1,500 and 2,500 people a day, according to Kari Cobb, a spokeswoman for Yosemite National Park.
Witnesses unsuccessfully urged the hikers to return to shore as they watched them step into the swift, cold water about 25 feet from the cliff's edge, park officials said.
There are signs at the head of the trail that warn of danger and fast-moving water, the park said.
"Visitors that want to go around guardrails ... it's up to them," Cobb said. "It's something that does happen and it's completely up to the visitor to know what safety concerns are around and take responsibility for their own actions."
Yosemite rangers continued to search Wednesday, concentrating on each side of the Merced River downstream from the fall, the release said.
After a huge winter snow and a cool spring and summer, the park's rivers and streams have been running at higher-than-normal levels for this year, and will remain high for several weeks, park officials said.
Before Tuesday's incident, there were three water-related deaths in Yosemite National Park this year.
[Posted 7:46 a.m. ET] A search is under way in Yosemite National Park for three people who may have been swept over the 317-foot-high Vernal Fall on the Merced River in eastern California.
Park rangers have closed the Mist Trail to the fall until at least noon Wednesday, saying they are conducting a search after receiving unconfirmed reports of one or more visitors being swept over the fall.
Witnesses told CNN affiliate KGPE-TV that three people were swept over the fall around 1:30 p.m. Tuesday.
â€śI saw the manâ€™s eyes when he went over the falls. That was devastating,â€ť witness Jacob Bibee told KGPE.
Other witnesses said two men and a woman went into the water and over the fall into a rocky pool below.
â€śI saw two that were holding each other and one that was floating alone through the water. And the reason that I looked was because this woman was screaming, running along the edge of the water,â€ť witness Dean Sabo told KGPE.