On Saturday, park rangers at Yosemite National Park searched for a California teenager who was swept over the edge of a nearly 600-foot waterfall while swimming.

Aleh Kalman, of Sacramento, Calif., was hiking on the Mist Trail with a church group and decided to take a dip in the water above Nevada Falls. Witnesses said the 19-year-old was about 150 feet from the edge of the falls when a strong current pulled him towards the deathly rapid current of the waterfall, the National Park Service said in a press release.

Kalman had been swimming ashore from a rock in the middle of the river at the time at about 2:45 p.m. A search team assisted by a California Highway Patrol helicopter spent the rest of the day unsuccessfully looking for him. They searched the area until nightfall, but could not locate the teenager. The search continued on Sunday, but still, he was not found. Park officials have closed the trail below the waterfall while the search for the young teen continues.

Officials said the Merced River, which travels over Nevada Fall, was flowing at about 500 cubic feet per second - "a very swift and powerful spring flow of water" - at the time of the accident. The temperature was reportedly in the low 50s.

This isn't the first waterfall-related incident at Yosemite's Merced River waterfalls. In August, a 6-year-old boy and his 10-year-old brother were killed after they were swept over Vernal Fall by the river's currents. Three hikers in their 20s also plunged to their deaths over Vernal Falls in July 2011.

The waterfall is a popular spot for tourists, but with the recent deaths, more security is in order to keep hikers safe. Authorities presume that the victim, Aleh Kalman, 19, didn't survive. "We believe it's impossible to survive a fall like that," a Park spokesman said.