Every October since 1979, the small town of Fayetteville, West Virginia, has welcomed daredevils by the hundreds to jump off the New River Gorge Bridge.
Though the jumpers are equipped with a rapid-deployment parachute, the plunge is nonetheless
extremely dangerous, requiring calm winds, clear conditions and a great degree of skill and precision.
The participants are BASE jumpers, a breed of people that thrive on the adrenaline rush felt when plummeting toward the earth from distances lower than that of skydiving.
The jumps provide a short free fall and a small window of time to deploy a parachute that saves them from a hard impact with Mother Earth.
The event, called Bridge Day, attracts more than 450 jumpers annually from more than 10 countries. This year, the event falls on Oct. 18.
"Bridge Day is centered around the fall foliage, which drives it toward a mid-October date each year," according to Jason Bell, BASE coordinator for the annual event.
"From a weather perspective, Bridge Day would probably be better suited for BASE jumping if it took place in August or September due to warmer temperatures," he said.
Air temperature is only a comfortability factor for the jumpers, however. Other weather factors, such as wind speed, wind direction, low/high pressure zones, vortices and the effects of winds over blacktop and/or large bodies of water are critical. An inaccurate reading of any of these variables could result in serious injury or death.
Jumpers who applied for permits to participate are relying on nature to deliver the perfect conditions: mild air and light winds, from 3-5 knots, blowing from a consistent direction.
"We like to see a little bit of wind since it counteracts the forward speed of our parachutes, making our landings softer with less running required," Bell said.
Jumpers land into the wind, hoping to slow their forward speed. If a parachute with a forward speed of 15 knots lands into winds of 5 knots, the forward speed on landing, as the jumper's feet touch the ground, is lowered to 10 knots.
Miscalculation of wind speeds at the landing area can be extremely dangerous - and in Fayetteville, it's often a ticket straight into the chilly whitewater New River Gorge.
Twenty-eight percent of Bridge Day jumpers find themselves in the river, before being plucked from the cold water by a rescue boat.
"BASE jumpers and meteorologists are birds of a feather, out of necessity," Bell said. "There are numerous factors that go into all of this..."
Bell has made more than 1,000 jumps in his 20 years of experience.
"No longer could I drive over a bridge, look at a tall antenna or peek out the window of a high-rise hotel without wondering how I can jump from it," Bell said.
As more than 80,000 people converge at the jump site this weekend, most will be spectating.
"Deep down inside, I think everyone wants to experience a BASE jump although some won't admit it," Bell said.
"BASE jumping is an exploration of human flight that offers much more than a quick free fall and parachute ride. Our sport offers exciting travels to some of the most interesting places in the world combined with the comeradery of a group of intellectual misfits. It's exciting. It's exhilarating. It defines me."