Wandering delirious with her dog through the groves of Ute Valley Park, a woman pale and sweating came across a group of people on a path.
They would be her saviors.
Her ankle was swollen and marked by two small punctures from a rattlesnake's fangs.
The woman, who has not been publicly identified, was the second in three days to be bitten by a venomous snake in the city's parks - signaling that snakes are beginning to emerge en masse from their winter dens.
Dr. Chris Layton pulled up to Ute Valley Park around midday Monday for one of his usual mountain bike rides, but the parking lot was filled with first responders.
The emergency physician rode his bicycle about a mile and a half into the park and saw the woman lying on a stretcher. Much of the snake's venom had made its way into her system, Layton said.
The woman had been walking her dog in the park when the snake bit her, Layton said. By the time she came upon other people, her blood pressure had dropped, making her incoherent.
It was difficult to tell where in the park she encountered the snake, or how far she had walked, Layton said.
"I'm surprised that she actually was able to stay upright, given how bad her blood pressure was," he said. "They were able to call for help right away and got a response very quickly, even given the remote area where the patient was located."
The woman was airlifted to Penrose Hospital, where she remained Friday. But, she was out of the intensive care unit and improving, Layton said.
More than 20 kinds of snakes live in Colorado, but rattlers are the state's only venomous snakes, said Tina Jackson, species conservation coordinator for Colorado Parks and Wildlife.
Cold-blooded, snakes are sensitive to changes in temperature, said Steve Mackessy, a University of Northern Colorado biology professor specializing in venomous snakes. When the temperature fluctuates above and below freezing, they're more likely to stay near where they hibernated in case the cold forces them to return.
But for the past month, rattlers and other snakes have been emerging from the underground lairs where they spent the winter.
"They're coming out now. They're starting to move," Mackessy said.
More snakes means more encounters with people on increasingly popular hiking trails in the city's parks and more chances for being bitten by a venomous rattler.
A few days before the woman was bitten in Ute Valley Park, another woman was bitten April 28 by a rattlesnake at Garden of the Gods near parking lot 10, said Fire Capt. Brian Vaughan.
Snakebites are relatively rare. Out of the millions of people who live in Colorado and the millions more who visit the state for outdoor activities, only 79 were bitten by snakes last year, said Shireen Banerji, a Rocky Mountain Poison & Drug Center clinical manager. The number of bites has been increasing slightly. There were 77 in 2016, 76 in 2015 and 65 in 2014.
Only one person is known to have died of a snakebite since 2014.
Rattlesnakes are pit vipers, a family of venomous snakes found in most part of the world. They have long, hinged fangs that permit deep penetration and injection of venom.
The best way to identify a rattlesnake is to look for its rattle, Jackson said.
Other snakes can try to mimic a rattlesnake - making a sound like a rattle or puffing out their cheeks - and interpreting a snake's coloring and markings can be confusing for the average person, she said. But even baby rattlesnakes has "a little knob" on the end of its tail, which grows each time it sheds.
"Rattlesnakes always will have a rattle at the end of their tail," she said. "If the tail comes to a point like a pencil, then that is not a venomous snake here in Colorado."
Jackson's advice when a hiker comes across any snake - not just a rattlesnake - is to give it a wide berth. If you're hiking with dogs or children, bring them close to you.
"If it's a rattlesnake and it's sitting out in the middle of the trail, if you don't need to continue, just turn around," she said.
"If you have some space and you can kind of get around him - and I'm talking, you know, at least 3 or 4 feet - just give him some space and let him be.
"If it's kind of a rocky trail or you've bumped into him too close, just definitely move slowly and let him kind of do what he's going to do."
People who hike or climb in rockier areas should always watch where they're putting their feet and hands, she said. But rattlesnakes don't often bite humans unless they're feeling threatened.
"Most of the time, rattlesnakes just use their venom to deal with their prey, and people are not prey for rattlesnakes, but if they need to protect themselves, they certainly have an effective way to do it."
A rattlesnake bite is "a progressive disorder," meaning it will get worse if it's not treated, Mackessy said.
First aid techniques are largely ineffective, he said.
"Emergency physicians that deal with snakebites say that the best first aid is your car keys, and that is to get in your car and get to a hospital as quickly as possible - or better yet, have somebody else take you there," Mackessy said.
Jackson said that many myths have emerged about treating snake bites.
"The old Westerns tell us lots of things we can do," she said. "Don't do any of those things. Call 911. Get help."
Mackessy emphasized that the risk of being bitten by a snake is low - lower than the chance of being in a car crash or being bitten by a dog.
"It's something that we're concerned about: Obviously we don't want people to get hurt, but you also don't want people to be so paranoid that they're not going to go outside, for example, and enjoy the outdoors," he said.
The Gazette's Jakob Rodgers contributed to this report.
Contact Ellie Mulder: 636-0198