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.
Joplin, Missouri
Joplin has a humid subtropical climate ("Cfa"), as defined by the Köppen climate classification system, with cool, dry winters and hot, humid summers; the severe weather season from April through June is the wettest time of year. The monthly daily average temperature ranges from in January to in July. On average, 51 days of + highs, 3.5 days of + highs, 14 days where the high fails to rise above freezing, and 1.9 nights of sub- occur per year. It has an average annual precipitation of , including an average of snow. Extremes in temperature range from on February 13, 1905 up to on July 14, 1954; the last or below and the last + reading occurred on February 3 and August 2, 2011, respectively. The city is located in Tornado Alley. Several storms have hit the city, including an F3 tornado in 1971, a tornado in 1973, an EF1 tornado on May 8, 2009, a blizzard on February 1, 2011, and an EF5 tornado on May 22, 2011.