A 25-year-old California woman is "lucky to be alive," in the words of rescuers, after a 100-foot fall down a waterfall in the state's hilly canyons.

The young woman was hiking with friends in Eaton Canyon in Altadena, near Los Angeles, Monday when she lost her footing and fell, according to authorities with the Los Angeles County Fire Department.

"When we were coming down [from a higher waterfall], the trail isn't really distinct, it's hard to figure out how to get down and we went the wrong way … but just went with it and she slipped and fell," the woman's boyfriend, Wilder Rees, told local television station KCAL9.

Fire officials responded to the scene around 6 p.m. and initially thought the woman, who was not identified, had fallen all 100 feet.  They later clarified that she slid 75 feet down the waterfall's cliff and then went into a free fall for the last 25 feet, according to local ABC affiliate KABC.

The only thing saving the woman, authorities said, was a safe spot in between two boulders on the ground.

"She landed on flat ground between two boulders. If she had hit the boulders, it would have been very bad,'" L.A. County Fire Department Capt. Mark Savage said.  "As it is, she's lucky to be alive."'

A rescue helicopter located the woman and transported her to a local hospital.  She arrived with only moderate injuries and is expected to recover, Savage said.