A 25-year-old woman from San Francisco was killed Tuesday falling down a waterfall in South Lake Tahoe, and a 24-year-old man from Petaluma is missing and still not found after meeting with a similar misadventure Sunday in Yosemite.

Recent San Diego State grad Hayden Klemenok, 24, who is originally from Petaluma, went missing Sunday after attempting to get some relief from the heat on a hike by Upper Chilnualna Falls in Yosemite National Park. As KTVU reports, Klemenok was with three friends on the hike around 2 p.m., and he was "on his hands and knees so he could dip his head and hat into the water." The friends said he lost his footing and slipped somehow, and disappeared into the water.

KTVU described the spot where he stopped as a "creek," but the Chronicle described it as the waterfall itself, saying that Klemenok "slipped and fell into fast-moving and freezing rapids."

Difficult terrain and still-remaining snow have made the search for Klemenok nearly impossible, and park officials have told his family that they believe he likely drowned.

"I was worried about things like dehydration, rattlesnakes, things like that," says his mother, Michelle Klemenok, speaking to the Chronicle. "I didn’t think about drowning. I knew he was a careful guy. … He was extremely physically fit, in the prime of his life. … I thought, well, if anyone can do [this backpacking trip], he can do it."

The Chronicle describes the missing young man as an "experienced backpacker," but his mother told KTVU that he was "not necessarily an experienced hiker."

Tragically, Klemenok's father, Kevin Klemenok, tells the Chronicle that he's "cried a lifetime" the past several days, and the family, after traveling by car to Yosemite to conduct a four-hour search of their own, is headed back to the Bay Area.

"“I arrived [thinking] we would find him battered or bruised," Kevin Klemenok says. "My son is five miles up in a canyon waterfall right now, and I’m leaving here with his three siblings, his mother, and an aunt, and we don’t have him. It’s horrible..."

A GoFundMe for the family has been started here.

Another, similar tragedy occurred Tuesday at Eagle Falls in South Lake Tahoe. 25-year-old Ishrat Azim of San Francisco was with friends, and they had pulled over to get a look at the waterfall, which is near Emerald Bay.

As El Dorado County Sheriff Capt. Michael Lensing explains to SouthTahoeNOW, Azim and her friends parked near the Eagle Falls parking lot, crossed the highway, and climbed over the guard rail to see the top of the waterfall. Azim then, reportedly, was holding a friend's hand while trying to dip her toes into the upper pool of the falls, but she slipped on wet rocks and was quickly pulled over the falls.

The incident was captured on cellphone video by a nearby group who had been recording the scenery.

Members of the El Dorado County Sheriff's Office Search and Rescue team later located Azim's body, and she was declared deceased.

Photo: Sam Goodgame