San Diego County Sheriff's Search and Rescue (SDSO) are warning hikers taking on Three Sisters Falls this spring and summer to be cautious and come prepared.
The rugged and strenuous trail, located in Julian, draws hundreds of visitors at its peak points.
In 2015, Search and Rescue crews came to the aid of 37 hikers. The number rose slightly in 2016, to 39 rescues. However, in 2017, just one person has been rescued from the trail from January to March.
SDSO Search and Rescue Reserve Commander Frank Motley said hikers still have not gotten the message that the hike is considered strenuous and difficult.
“The challenge with Three Sisters is that it’s easy to get down there,” Motley said.
“But you forget you have the hard hike back up," Motley added.
On busy holidays, when traffic is backed up bumper to bumper coming to the trail head, Search and Rescue officials wait on the trail with extra water and medical equipment in case someone comes in unprepared and needs some help, Motley said.
“Because you’re up in Julian, you think it’s going to be cool and nice, but it’s a high desert hike,” he said.
The reality is much different: there is a lot of direct sunlight and high heat along the trail. You may even see rattlesnakes.
Even people who consider themselves in shape are warned to take extra precautions. There are parts of the hike where you are on all fours, Motley said.
Sheriff’s officials see it often, especially during the summer months: some hikers will bring little to no water, or bring alcohol to drink at the bottom of the trail. Then, on the way up, they get dehydrated.
Julie Wright, a San Diegan hiking the trail a few weekends ago, said she saw many people starting the trail with little to no water.
"I just think people don't exactly know what they're getting into," Wright said.
The hiking experience was a stark difference from Cedar Creek Falls, a nearby trail popular with San Diegans. Hikers need permits to hike in the area, Wright said, and when she started the trail, someone stood at the trail head and warned hikers that it would be a difficult hike back up.
At Three Sisters, she said, they saw one sign warning them about wildfire danger but nothing else.
"It’s a real danger, it has a history, and it’s really attractive right now because of the volume of water," Wright said. "There was a steady stream of people."
Before making the decision to go, Wright said, she read online reviews to check what she was getting into.
"If you go look at reviews, if you go to AllTrails.com, for instance, which I did, I read a review, and it said, ‘This trail is a beast,'" she said.
For hikers looking to take on the challenge, Wright and Motley have similar key recommendations: bring plenty of water and wear proper footwear (no flip flops, Motley says). Motley recommends a liter of water per hour.
“First and most important – let someone know where and when you’re going,” Motley said. “That helps us a lot.”
At the end of the day, Wright said, it's a beautiful hike -- and do-able, with the proper preparation.
"It’s a beautiful location, what a wonderful thing to be able to hike in and see the running falls," she said. "It's awesome."
NBC 7's R. Stickney contributed to this report.