You know it's going to be a bad day when you find yourself falling through the air without a parachute! But let's say that, somehow, you were to fall out of an airplane and found yourself in that exact situation.
You have to keep that you have to think fast. If you fall out at 12,000 feet (about 2 miles up), you only have about 60 seconds before you hit the ground. In free fall, you fall at about 125 miles per hour (mph) if you have your arms and legs extended, and at that speed you will travel about 12,000 feet in one minute.
The first thing to do is to look for a body of water. If you can dive into water, it won't feel good at 125mph, but you'll survive if the water is deep enough -- at least 12 feet or so. Steer toward the water (it's helpful if you've been skydiving before and know how to steer as you are falling), and dive right in.
If there's no water around, then you need to try something else. One person in World War II survived a jump without a parachute from about 18,000 feet. He fell through the branches in a pine thicket and landed in deep snow. So you might try looking for some trees and hope for the best.
Lacking water or trees -- for example, you're falling in an urban area and can't spot a rooftop pool -- your next option is to look for something big with the hope that it will break your fall. For example, landing on the roof of an RV, a mobile home or a truck's trailer is a possibility.
These structures are not extremely strong. When you hit them, they'll break and absorb some of the energy of the fall. Whether it will be enough energy or not is an open question. There's only one way to find out, but we don't recommend you try it! And while we do like to do our own research and take things apart here at HowStuffWorks, you have to draw the line somewhere. This is definitely a line.
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