"In Kuwait, after the end of the Gulf War, the Kuwaitis celebrated by firing weapons into the air—and 20 Kuwaitis died from falling bullets" - bob

"In Los Angeles, between the years 1985 and 1992, doctors treated 118 people for random falling-bullet injuries at King/Drew Medical Center, and 38 of them died [2]. Practically all of the injuries were due to happy holiday weekend revelers" - bob

"The bullet’s velocity required for skin penetration is between 148 and 197 feet per second. A velocity of less than 200 feet per second, which is easily obtained by a celebratory gunfire, is capable of fracturing bone and even causing intracranial penetration [4]. Spent bullets have the capability of reaching up to 600 feet per second during their downfall, and thus they have the ability to inflict damage to multiple body cavities" - bob

In Turkey, many people die every year because other people shoot in the air to celebrate things like soccer victories. It's almost a common thing. - Can Mert Bozkurt

If you fire directly up, the bullet stops at the top of its arc and tumbles down harmlessly. If you fire with a ballistic trajectory its terminal velocity is much higher, and can be deadly. - Gabe