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ST. LOUIS, Mo. – When a powerful EF-4 tornado struck the St. Louis metro on April 22, 2011, amazingly no one was killed. Sadly, the same cannot be said when a massive EF-5 tornado struck Joplin, MO, one month later.

On May 22, 2011, one of the deadliest tornadoes on record struck the southwest Missouri town of Joplin. The National Weather Service office in Springfield, Missouri, had been tracking the severe weather threat all day.

“Once we saw an indication that debris has been lofted ten, fifteen thousand feet up into the air. That’s when we knew that an extremely unusual event was going through a very populated area. That’s when we became very, very concerned,” says Steve Runnels, the Warning Coordination Meteorologist for NWS Springfield.

Winds in excess of 200 mph resulted in catastrophic damage, killing 158 and injuring more than 1,000. Touching down around 5:30 pm on the western edge of the city, the tornado chewed up homes and businesses as it moved east. St. John’s Medical Center took a direct hit. Sections of Joplin High School were destroyed and stores in the main business district were leveled.

“Moving anywhere from twenty to thirty-five miles per hour. Keep in mind that this was about three-quarters of a mile wide. So, the residence time of that spinning, violent tornado going through the hospital area, the residential area, and eventually the commercial area, the east side of Joplin, it’s easy to see why we had fatalities,” explains Runnels.

The tornado kept heading east-southeast, crossing Interstate 44, where it flung cars and road signs, and finally lifting at 6:12pm northeast of Granby, Missouri. It traveled 21 miles and destroyed more than 7,000 buildings. In the wake of the disaster, lessons were learned. Upgrades of satellite and radar technology paint a clearer picture for forecasters. And changes were made to the way thunderstorm and tornado warnings are issued.

“What the National Weather Service did following Joplin was to put additional information in our warnings to confirm those threats and, in particular, the intensity of that tornado,” says Runnels

That extra info, relayed via broadcast media, weather radio, and social media, is designed to get people take action more quickly.

“Ultimately, if we can get information to people on confirmation of threat, we will save lives by getting them to go to shelter faster.”

Joplin is ranked 7th among deadliest tornadoes in United States history. Number One on that list is the Tri-State Tornado in March 1925. The St. Louis Tornado on May 27, 1876, comes in third.

Click here for a look at the NWS Springfield’s Story Map of the Joplin tornado.