page_title: May 2009 Southern Midwest derecho
section_title: Southeastern Missouri and southwestern Illinois
hierarchical_section_title: May 2009 Southern Midwest derecho / Effects / Southeastern Missouri and southwestern Illinois
caption_attribution_description: An EF-0 tornado north of Royalton, IL on May 8, 2009
context_page_description: The May 2009 Southern Midwest Derecho was an extreme progressive derecho and mesoscale convective vortex 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." A new 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 to 106 mph was recorded by a backup anemometer at the Southern Illinois Airport after official National Weather Service equipment failed.
context_section_description: As the initial line weakened, the mesoscale convective vortex on the northern end began to strengthen and separate from the squall line.  A long-lived supercell formed within the MCV in Madison County, Missouri, producing hail up to baseball size and a few tornadoes, in addition to the more widespread, damaging, straight-line winds throughout the area.
  Numerous trees were knocked over from Shannon County, Missouri—near the Current and Jacks Fork rivers, in the Ozark National Scenic Riverways preserve—northward through the Mark Twain National Forest and other forested public conservation lands.  Devastation was especially pronounced in the area west of Ironton, Missouri, around the popular Johnson's Shut-Ins State Park and the Bell Mountain Wilderness area. Over 50 miles of the long-distance Ozark Trail were damaged, requiring many months of repairs to rehabilitate.
  As the MCV crossed the Mississippi River and entered into more populated areas, it strengthened greatly, while it nearly separated from the initial line.  Numerous buildings were severely damaged or destroyed throughout southern Illinois. Immediately after the MCV struck, Carbondale was reported to be virtually impassable due to the amount of debris on roadways. Marion, Murphysboro, Grand Tower, Johnston City, Herrin, Energy, and Carterville, Illinois, declared curfews and states of emergency due to power outages and the massive amounts of damage caused by the storms. Some of these cities were even left without water due to the power outages.  In the city of Carbondale, damage was estimated at US$3,000,000, excluding damage at Southern Illinois University. Officials deemed 34 buildings a "total loss" and reported that 3,000 trees were felled throughout the city.
  Preliminary estimates placed damages at Southern Illinois University in excess of US$5,000,000. Numerous buildings on campus sustained roof damage, and nearly 100 windows were blown out of residence halls. Due to infrastructure damage from the storm, most communication by land line and mobile phone was reported to be impossible.  In Carterville, Illinois, officials found 17 buildings to be a total loss. The city's public works garage was shifted off its foundation, and the police station sustained damage.  In Franklin County, Illinois, 13 buildings were deemed to be beyond repair; damage assessments found that 184 buildings received some kind of damage from the storm. Winds were estimated between 80 and 90 mph (130 and 140 km/h) in the county. At one point, 68,000 people were left without power in southern Illinois alone, prompting unusual methods to restore power, such as using helicopters to clear debris and position power poles.
caption: Picture of an EF-0 tornado north of Royalton, Illinois, on May 8, 2009
exif: {}