PHOENIX - An 18-year-old hiker sustained serious injuries after falling off a cliff at Camelback Mountain Sunday.

The hiker was conscious but in critical condition when Phoenix Fire Department technical rescue teams reached him. By Monday afternoon, his condition was upgraded to stable, according to a Phoenix park ranger who assisted with his rescue.

Ranger David Metzler says the man, simply known as "Jimmy," had been on the Bobby's Rock Loop when he left the trail to free climb in an area known as August Canyon. Metzler said the area is an established rock climbing spot on the west side of Camelback Mountain.

The young man had been hiking with his 14-year-old sister when he got into trouble.

“It just sounded like a scream,” said Miguel Lopez, who was also hiking at the time and heard the scream over the music in his headphones. “Honestly, like someone was having a good time but we now know that's not the case.”

The ranger said Jimmy was wearing what looked like lightweight Vans shoes and had no other climbing equipment.

"(It's) easy to slip off with that type of rock -- that rock's slippery anyways," Metzler said.     

Phoenix Fire Department spokesperson Rob McDade said Jimmy fell 75 to 100 feet. Rescue crews brought the man down the mountain to an area where he could be lifted into a rescue helicopter.

“They were off the main trail in an area that is primarily used for recreational climbing and rappelling with ropes and gear,” said Phoenix FD Cpt. Tom Taylor, who’s part of the department’s special operations team.

At first, the only thing leading firefighters to the teen’s general area were pings from his cell phone and help from their chopper in the air.

“They were up tight against the cliff face and they (firefighters) needed to make a steep-angle evacuation,” said Taylor. “Everybody has their tasks to do to give this person their best chance at surviving."

The teen was stuck 100 feet down a ravine with multiple traumatic injuries.He was immediately flown to a local emergency room.

Metzler says the wayward hiker violated one of the core principles of the City of Phoenix "Take a Hike -- Do it Right" campaign: Don't trailblaze! The education program started two years ago in response to a spike in rescues.

The program includes signs at trailheads alerting hikers to levels of trail difficulty and proper routes. Hikers are also advised to carry enough water and supplies to stay fit during hikes. Rangers are also positioned at trailheads at the more popular routes in the greater-Phoenix area. They will engage with nearly every hiker or group of hikers, and quickly assess the strength and preparation of the person or persons.

"We'll find out how far they're planning on going up, have they ever done the mountain before?" he said. "How much water are they carrying? Do their friends and family know they're out hiking today?"

They're also there to remind hikers not to trailblaze.

"The safest way to the summit is by staying on the main trail," Metzler said.

And yet, he constantly has to remind hikers how important it is for them to resist the temptation to venture off established trails.

"That's why we tell everybody, 'Stick to the program -- Take a Hike, Do it Right,'" Metzler implored. "Stay on the trail. So that way, when these instances and issues come up, we know where you're at, and the quickest way to locate you if we need to rescue you."

Lopez said the teen's fall has him reconsidering some of his hiking practices.

“It's terrifying,” said Lopez, “especially because I hike myself a lot and it’s just a reminder that we always gotta be careful and stay on the path.”

For more info on the "Take a Hike -- Do it Right" program, visit the City of Phoenix's parks website.