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Sport of jumping from fixed objects using a parachute

BASE jumping (/b//eɪ//s/) is the recreational sport of jumping from fixed objects, using a parachute to descend safely to the ground. "BASE" is an acronym that stands for four categories of fixed objects from which one can jump: buildings, antennas (referring to radio masts), spans (bridges), and earth (cliffs). Participants exit from a fixed object such as a cliff, and after an optional freefall delay, deploy a parachute to slow their descent and land. A popular form of BASE jumping is wingsuit BASE jumping. In contrast to other forms of parachuting, such as skydiving from airplanes, BASE jumps are performed from fixed objects which are generally at much lower altitudes, and BASE jumpers only carry one parachute. BASE jumping is significantly more hazardous than other forms of parachuting, and is widely considered to be one of the most dangerous extreme sports.

Fausto Veranzio is widely believed to have been the first person to build and test a parachute, by jumping from St Mark's Campanile in Venice in 1617 when he was over 65 years old. However, these and other sporadic incidents were one time experiments, not the actual systematic pursuit of a new form of parachuting.

There are precursors to the sport dating back hundreds of years. In 1966, Michael Pelkey and Brian Schubert jumped from El Capitan in Yosemite National Park. The acronym "B. A. S. E." (now more commonly "BASE") was later coined by filmmaker Carl Boenish, his wife Jean Boenish, Phil Smith, and Phil Mayfield. Carl Boenish was an important catalyst behind modern BASE jumping, and in 1978 he filmed jumps from El Capitan, made using ram air parachutes and the freefall tracking technique. While BASE jumps had been made prior to that time, the El Capitan activity was the effective birth of what is now called BASE jumping. After 1978, the filmed jumps from El Capitan were repeated, not as an actual publicity exercise or as a movie stunt, but as a true recreational activity. It was this that popularized BASE jumping more widely among parachutists. Carl Boenish continued to publish films and informational magazines on BASE jumping until his death in 1984 after a BASE jump off the Troll Wall. By this time, the concept had spread among skydivers worldwide, with hundreds of participants making fixed object jumps. During the early eighties, nearly all BASE jumps were made using standard skydiving equipment, including two parachutes (main and reserve), and deployment components. Later on, specialized equipment and techniques were developed specifically for the unique needs of BASE jumping. Nowadays, recognizing the sport's growing appeal and the potential for high impact marketing, companies like Red Bull have stepped in to sponsor athletes, further elevating the sport's profile.

BASE numbers are awarded to those who have made at least one jump from each of the four categories (buildings, antennae, spans and earth). When Phil Smith and Phil Mayfield jumped together from a Houston skyscraper on 18 January 1981, they became the first to attain the exclusive BASE numbers (BASE #1 and #2, respectively), having already jumped from an antenna, spans, and earthen objects. Jean and Carl Boenish qualified for BASE numbers 3 and 4 soon after. A separate "award" was soon enacted for Night BASE jumping when Mayfield completed each category at night, becoming Night BASE #1, with Smith qualifying a few weeks later. Upon completing a jump from all of the four object categories, a jumper may choose to apply for a "BASE number", awarded sequentially. The 1000th application for a BASE number was filed in March 2005 and BASE #1000 was awarded to Matt "Harley" Moilanen of Grand Rapids, Michigan. as of 2017, over 2,000 BASE numbers have been issued.

In the early days of BASE jumping, people used modified skydiving gear, such as by removing the deployment bag and slider, stowing the lines in a tail pocket, and fitting a large pilot chute. However, modified skydiving gear is then prone to kinds of malfunction that are rare in normal skydiving (such as "line overs" and broken lines). Modern purpose built BASE jumping equipment is considered to be much safer and more reliable.

The biggest difference in gear is that skydivers jump with both a main and a reserve parachute, while BASE jumpers carry only one parachute. BASE jumping parachutes are larger than skydiving parachutes and are typically flown with a wing loading of around Vents are one element that make a parachute suitable for BASE jumping. BASE jumpers often use extra large pilot chutes to compensate for lower airspeed parachute deployments. On jumps from lower altitudes, the slider is removed for faster parachute opening.

BASE jumpers use a single parachute harness and container system. Since there is only a single parachute, BASE jumping containers are mechanically much simpler than skydiving containers. This simplicity contributes to the safety and reliability of BASE jumping gear by eliminating many malfunctions that can occur with more complicated skydiving equipment. Since there is no reserve parachute, there is little need to cut away their parachute, and many BASE harnesses do not contain a 3 ring release system. A modern ultralight BASE system including parachute, container, and harness can weigh as little as .

When jumping from high mountains, BASE jumpers will often use special clothing to improve control and flight characteristics in the air. Wingsuit flying has become a popular form of BASE jumping in recent years, that allows jumpers to glide over long horizontal distances. Tracking suits inflate like wingsuits to give additional lift to jumpers, but maintain separation of arms and legs to allow for greater mobility and safety.

BASE jumps can be broadly classified into low jumps and high jumps. The primary distinguishing characteristic of low BASE jumps versus high BASE jumps is the use of a slider reefing device to control the opening speed of the parachute, and whether the jumper falls long enough to reach terminal velocity.

Low BASE jumps are those where the jumper does not reach terminal velocity. Sometimes referred to as "slider down" jumps because they are typically performed without a slider reefing device on the parachute. The lack of a slider enables the parachute to open more quickly. Other techniques for low BASE jumps include the use of a static line, direct bag, or P. C. A. (pilot chute assist). These devices form an attachment between the parachute and the jump platform, which stretches out the parachute and suspension lines as the jumper falls, before separating and allowing the parachute to inflate. This enables the very lowest jumps—below to be made. It is common in the UK to jump from around the 150 feet (46 m) mark, due to the number of low cliffs at this height. Base jumpers have been known to jump from objects as low as 100 feet (30 m), which leaves little to no canopy time and requires an immediate flare to land safely.

Many BASE jumpers are motivated to make jumps from higher objects involving free fall. High BASE jumps are those which are high enough for the jumper to reach terminal velocity. High BASE jumps are often called "slider up" jumps due to the use of a slider reefing device. High BASE jumps present different hazards than low BASE jumps. With greater height and airspeed, jumpers can fly away from the cliff during freefall, allowing them to deploy their parachute far away from the cliff they jumped from and significantly reduce the chance of object striking. However, high BASE jumps also present new hazards such as complications resulting from the use of a wingsuit.

Tandem BASE jumping is when a skilled pilot jumps with a passenger attached to their front. It is similar to skydiving and is offered in the US and many other countries. Tandem BASE is becoming a more accessible and legal form of BASE jumping.

BASE competitions have been held since the early 1980s, with accurate landings or free fall aerobatics used as the judging criteria. Recent years have seen a formal competition held at the high Petronas Towers in Kuala Lumpur, Malaysia, judged on landing accuracy. In 2012 the World Wingsuit League held their first wingsuit BASE jumping competition in China.

BASE jumps are typically performed from much lower altitudes than in skydiving. Skydivers are required to deploy their main parachute above 2000 feet (610 m) altitude. BASE jumps are frequently made from less than 486 feet (148 m). A BASE jump from a 486 feet (148 m) object is only about 5.6 seconds from the ground if the jumper remains in free fall. Standard skydiving parachute systems are not designed for this situation, so BASE jumpers use specially designed harnesses and parachute systems. Many BASE jumps, particularly in the UK are made from around 150 feet (46 m) due to the number of low cliffs at this height. Jumpers will use a static line method to ensure their canopy is extracted as they jump, as at this height, it is too low to freefall. BASE jumps generally entail slower airspeeds than typical skydives (due to the limited altitude), a BASE jumper does not always reach terminal velocity. Skydivers use the airflow to stabilize their position. BASE jumpers, falling at lower speeds, have less aerodynamic control. The attitude of the body at the moment of jumping determines the stability of flight in the first few seconds, before sufficient airspeed has built up to enable aerodynamic stability. On low BASE jumps, parachute deployment takes place during this early phase of flight. If the parachute is deployed while the jumper is unstable, there is a high risk of entanglement or malfunction. The jumper may also not be facing the right direction. Such an off heading opening is not as problematic in skydiving, but an off heading opening that results in object strike has caused many serious injuries and deaths in BASE jumping. BASE jumps are more hazardous than skydives primarily due to proximity to the object serving as the jump platform. BASE jumping frequently occurs in mountainous terrain, often having much smaller areas in which to land in comparison to a typical skydiving dropzone. BASE jumping is significantly more dangerous than similar sports such as skydiving from aircraft. The legal position is different at other sites and in other countries. For example, in Norway's Lysefjord (from the mountain Kjerag), BASE jumpers are made welcome. Many sites in the European Alps, near Chamonix and on the Eiger, are also open to jumpers. Some other Norwegian places, like the Troll Wall, are banned because of dangerous rescue missions in the past.

The National Park Service has banned BASE jumping in U. S. National Parks. The authority comes from 36 CFR 2.17(3), which prohibits, "Delivering or retrieving a person or object by parachute, helicopter, or other airborne means, except in emergencies involving public safety or serious property loss, or pursuant to the terms and conditions of a permit." Under that Regulation, BASE is not banned, but is allowable if a permit is issued by the Superintendent. The 2001 National Park Service Management Policies state that BASE "is not an appropriate public use activity within national park areas " (2001 Management Policy 8.2.2.7.) However, Policy 8.2.2.7 in the 2006 volume of National Park Service Management Policies, which superseded the 2001 edition, states "Parachuting (or BASE jumping), whether from an aircraft, structure, or natural feature, is generally prohibited by 36 CFR 2.17(a)(3). However, if determined through a park planning process to be an appropriate activity, it may be allowed pursuant to the terms and conditions of a permit." Once a year, on the third Saturday in October ("Bridge Day"), permission to BASE jump has explicitly been granted at the New River Gorge Bridge in Fayetteville, West Virginia. The New River Gorge Bridge deck is 876 feet (267 m) above the river. This annual event attracts about 450 BASE jumpers and nearly 200,000 spectators. 1,100 jumps may occur during the six hours that it is legal, providing conditions are suitable. During the early days of BASE jumping, the NPS issued permits that authorized jumps from El Capitan. This program ran for three months in 1980 and then collapsed amid allegations of abuse by unauthorized jumpers. The NPS has since vigorously enforced the ban, charging jumpers with "aerial delivery into a National Park". One jumper drowned in the Merced River while evading arresting park rangers, having declared "No way are they gonna get me. Let them chase me—I'll just laugh in their faces and jump in the river". Despite incidents like this one, illegal jumps continue in Yosemite at a rate estimated at a few hundred per year, often at night or dawn. El Capitan, Half Dome, and Glacier Point have been used as jump sites.

A study of BASE jumping fatalities estimated that the overall annual fatality risk in 2002 was one fatality per 60 participants. A study of 20,850 BASE jumps from the Kjerag Massif in Norway reported nine fatalities over the 11 year period from 1995 to 2005, or one in every 2,317 jumps. However, at that site, one in every 254 jumps over that period resulted in a nonfatal accident.