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.
2011 Hackleburg–Phil Campbell tornado
In total, this tornado killed 72 people, all in Alabama. This made it the deadliest single tornado ever to strike the state of Alabama as well as (at the time) the deadliest in the United States since the 1955 Udall, Kansas tornado that killed 80 people. This death toll would go on to be exceeded by the Joplin EF5 tornado less than a month later. Damage from the tornado amounted to $1.29 billion, making this one of the costliest tornadoes in U.S. history. This tornado also had the longest track of any tornado in the outbreak, with its path extending across Northern Alabama and into Tennessee.