Missouri
Located in Tornado Alley, Missouri also receives extreme weather in the form of severe thunderstorms and tornadoes. The most recent tornado in the state to cause damage and casualties was the 2011 Joplin tornado, which destroyed roughly one-third of the city of Joplin. The tornado caused an estimated $1–3 billion in damages, killed 159 (+1 non-tornadic), and injured over 1,000 people. It was the first EF5 to hit the state since 1957 and the deadliest in the U.S. since 1947, making it the seventh deadliest tornado in American history and 27th deadliest in the world. St. Louis and its suburbs also have a history of experiencing particularly severe tornadoes, the most recent memorable one being an EF4 tornado that damaged Lambert-St. Louis International Airport on April 22, 2011. One of the worst tornadoes in American history struck St. Louis on May 27, 1896, killing at least 255 and causing $10 mil. damage ($3.9 bil. damage in 2009) or $ in today's dollars.
Emergency communication system
161 people were killed and at least 990 injured when an EF5 multiple-vortex tornado hit Joplin, Missouri. Because Joplin is located in a tornado-heavy area of the country, many people considered the tornado sirens routine and ignored them. Instead, many residents waited until they received confirmation from another, non-routine, source, such as seeing the tornado, a radio or TV report, or hearing a second siren. In the aftermath, an assessment team recommended that emergency warnings take risk perception into account to convey a sense of urgency. NOAA Officials are considering ways to change the warning system to distinguish smaller tornadoes from more deadly ones.