* Never cave alone, and always tell someone where you are going
* Wear clothing suitable for the cave's temperature and wetness
* Each person in the party should have 3 sources of light, including one that can be mounted on the head
* Always wear a sturdy helmet
Source: Walker County Emergency Management
More than 700 University of Florida students held a vigil Sunday night to mourn two students who died in a Walker County, Ga., cave Saturday.
Rescue workers believe Grant Lockenbach, 20, and Michael Pirie, 18, died of hypothermia while trapped by their rappelling ropes in a frigid waterfall cascading inside Ellison's Cave, Walker County Sheriff Steve Wilson said.
"Those two were just really solid young men," said Don Mauldin, a regional director of the Fellowship of Christian Athletes, of which Lockenbach was a president and Pirie a member. "They were hard workers, good friends and sacrificial leaders. A lot of people are going to miss them terribly."
Lockenbach, Pirie and eight other students drove up from Gainesville, Fla., Friday night and entered the cave Saturday morning to do some "basic exploring," said David Ashburn, director of Walker County Emergency Management.
Witnesses told officials that someone dropped a bag down the cave's first large pit, estimated to be a 125-foot drop. Lockenbach rappelled down to retrieve the bag but got tangled in his ropes about 100 feet down. Cold water pouring over the cliff's face drenched him, and he called for help. That's when Michael Pirie rappelled down and also got stuck.
"The [other students] couldn't really communicate because of the volume of the water," said Wilson. "They could hear them calling for about 30 minutes, but then their voices faded out."
Wilson explained that hypothermia could have set in as quickly as 15 minutes.
The two men were wearing shorts and T-shirts, Ashburn said.
"They just weren't prepared for the elements, or for those kinds of temperatures," Ashburn said. According to rescuers, the men had helmets.
Once their companions called 911, it took rescuers more than eight hours to retrieve the bodies, according to Wilson. They have been sent to an Atlanta crime lab for an autopsy.
Mauldin said the trip was to celebrate Lockenbach's birthday, which is Feb. 19. He said Lockenbach was a committed member of UF's ROTC program and that Pirie was in the UF marching band drum line.
"They knew and affected a lot of people. It's just a roller coaster of emotion here," he said.