Firefighters were called to Eaton Canyon around 11:30 a.m. A group of four hikers had somehow reached the upper falls of the canyon, and the 17-year-old girl and 18-year-old male slipped and fell.
The girl was pronounced dead at the scene, while the 18 year old was airlifted to Huntington Memorial Hospital with critical but non life-threatening injuries. The other two hikers were airlifted down off of the waterfall trail.
"They had fallen down near the trail, they were on the westside of the trail, but they were maybe 30 feet off of the trail, but they were 200 feet above that," said Los Angeles County Fire Capt. Raymon Mitchison.
The main trail in that part of the canyon leads to a waterfall, but a second waterfall is located above the first and is accessible through what is known as an unofficial trail. There are signs posted along the trail warning hikers that they should proceed at their own risk if attempting to reach the perilous upper falls. Numerous fatalities have occurred on that part of the trail.
"First it's a family-friendly trail, but then there's a ridge that people like to climb up, and it's really steep and really loose ground, and pretty much anything that you touch can fall out," said hiker Jesse Adamczyk.
Officials say they do not know for sure how the four hikers reached the upper waterfall.