2009 Super Derecho
A screenshot from the Paducah, Kentucky, radar of the mesoscale convective vortex portion of the derecho near Carbondale, Illinois. This screenshot is from the approximate time the 106 mph (171 km/h) wind gust was recorded at the Southern Illinois Airport. | |
| Date(s) | May 8, 2009 |
|---|---|
| Duration | 15 hours, 28 minutes (tornado outbreak) |
| Tornado count | 39 confirmed |
| Strongest tornado1 | EF3 tornado |
| Fatalities | Four direct, two indirect |
| Damage costs | ~$500 million |
| 1Most severe tornado damage; see Fujita scale | |
The tornado outbreak and derecho of May 8, 2009, colloquially known as the 2009 Super Derecho, was an extreme progressive derecho, tornado outbreak, and mesoscale convective vortex (MCV) event that struck southeastern Kansas, southern Missouri, and southwestern Illinois on May 8, 2009. Thirty-nine tornadoes, including two of EF3 strength on the Enhanced Fujita Scale, were reported in addition to high non-tornadic winds associated with the derecho and MCV. Due to the abnormal shape of the storm on radar and the extremely strong winds, many called this an "inland hurricane." Notably, this storm had a defined eye akin to a tropical storm, which occurred alongside intense sustained winds of 70–90 mph (110–140 km/h) at the surface level, not associated with the bowing convection typical of a derecho. A new proper class of storm, the "Super Derecho," has been used to describe this event after analysis in 2010. Embedded supercells produced hail up to baseball size in southern Missouri, a rare event in a derecho. A wind gust of 106 mph (171 km/h) was recorded by a backup anemometer at the Southern Illinois Airport after official National Weather Service equipment failed. This derecho was the last of a series of derechos that occurred at the beginning of May.