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.
Tri-State Tornado
The Tri-State Tornado of Wednesday, March 18, 1925 was the deadliest tornado in United States history. It was also the most exceptional tornado during a major outbreak of at least 12 known significant tornadoes, spanning a large portion of the Midwestern and Southern United States. This one tornado alone inflicted 695 fatalities, more than twice as many as the second deadliest, the Great Natchez, Mississippi Tornado of May 7, 1840. The track left by the tornado was the longest ever recorded in the world as it crossed from southeastern Missouri, through southern Illinois, then into southwestern Indiana. Although not officially rated by NOAA, it is recognized by most experts (such as Tom Grazulis and Ted Fujita) as an F5 tornado, the maximum damage rating issued on the Fujita scale.