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 Joplin tornado
The tornado then continued on an east to east-southeast trajectory towards Interstate 44 where it weakened; nonetheless, vehicles were blown off the highway and mangled near the U.S. Route 71 (Exit 11) interchange. The damage at and around the interchange was rated EF2 to EF3. The weakening tornado continued to track into the rural areas of southeastern Jasper County and northeastern Newton County where damage was generally minor to moderate, with trees, mobile homes, outbuildings, and frame homes damaged mainly at EF0 to EF1 strength. The tornado lifted east of Diamond at 6:12 pm CDT (23:12 UTC) according to aerial surveys. The tornado's total track length was at least long. Overall, 6,954 homes were destroyed, 359 homes had major damage and 516 had minor damage, 158 people were killed, and 1,150 others were injured along the path. A separate EF2 tornado touched down near Wentworth from the same supercell about east-southeast of Joplin.