Emergency communication system
161 people were killed and at least 990 people were injured when an EF5 tornado hit Joplin, Missouri. Because Joplin is in a tornado area of the United States, many people thought the tornado sirens were normal and ignored them.  Instead, many people who lived there waited until they got more information another way, such as seeing the tornado, a radio or tv report, or hearing another, second siren. Afterward, a special group of people recommended that emergency warnings should consider  how people understand emergencies and make them think about how quickly they need to respond. NOAA officials are thinking about ways to change the warning system to warn people about smaller tornadoes in a different way than the bigger ones.