Unfortunately, mortality is not an unusual price to pay for a brief adrenaline boost. The probability of surviving a fall from a height increases with increasing body mass. A person who weighs 180 pounds (82 kg) has a 50% chance of survival if he or she falls from a height of 60 feet (18 m). But a person who weighs 390 pounds (183 kg) would have only a 5% chance of survival if he or she fell from the same height. The likelihood of survival after a fall varies depending on the type of cliff used in the jump. For example, someone who jumps off a 30-foot (9 m) high rock face has about a 1 in 4 chance of survival. However, if that person were to jump off a 100-foot (30 m) high bridge there would be almost no chance of survival because the fall itself is the most dangerous part of the cliff dive. The person would probably die before reaching the water because of internal bleeding caused by his or her broken bones. Cliff diving is dangerous because it involves falling down mountainsides or over cliffs. There are many factors that can increase or decrease a person's chances of survival including weight, experience, weather conditions, and equipment quality.