What Do You Know for Sure?

Journalist Amanda Ripley is the author of The Unthinkable: Who Survives When Disaster Strikes—and Why (Crown).

1. We are almost always our own first responders because official help cannot arrive quickly enough.

2. People think that if you're in a plane crash you're doomed, but between 1983 and 2000, 56 percent of passengers in serious crashes lived. Those who have an aisle seat and read the air safety cards are the most likely to survive.

3. The biggest misconception about catastrophes is that people panic. More often, our reactions slow down, even stop. After the planes hit the World Trade Center, hundreds of workers turned off their computers and cleaned up their desks. The average time before evacuating was six minutes. You have to move—and move quickly.

4. People may be most afraid of terrorists and freak viruses, but fire, floods, and lightning are the disasters to prepare for—to practice for.

5. Do every fire drill. Have the muscle memory of how to do things under extreme stress. 

— As told to Amanda Robb