Updated: What was it that caused the May 8 windstorm?

 

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What was it?

First, we may want to start out with what it was not. It was not an inland hurricane, although it may have felt like one. A hurricane is tropical in nature, this system that we experienced was convective. It was not a large tornado. Although there were several small tornadoes embedded within the widespread damaging winds.

 

The storm system is classified as a Derecho. If you want to learn more about derechos, there is a nice web site put together by the Storm Prediction Center. This derecho would probably be determined to be a progressive derecho

However, this was not your typical derecho. Often on these types of systems in the northern hemisphere, a bookend vortex, or comma head develops on the north side of the system. The comma head usually acts like a large paddle wheel on a boat and helps to focus strong winds in behind the bowing squall line. A large portion of the damaging winds occurred on the southwest and southern end of the comma head.

 

Although it is still under study, it appears that at least some of the tornadoes in this case occurred with the comma head. This is not unusual, in fact research work in the 1980s documented a case of a derecho that moved through central Illinois in which tornadoes were associated with the comma head.

The system that moved through on May 8 had an unusually large bookend vortex. Numerical simulations completed in the early 1990s and some observational studies documented commahead vortexes were on average 12 nm in diameter. The comma head on the May 8th storm was 30 to 40 nm in diameter. In fact, this is the largest bookend vortex that some experts have seen in their careers. This will be the subject of more in-depth research for years to come.


 

Overview: A widespread damaging wind event with isolated embedded tornadoes occurred in southern Illinois and parts of southeast Missouri on Friday, May 8.

Peak wind gusts were measured over 80 mph at Marion and Carbondale, IL. The peak gust recorded by the automated system at the Carbondale airport was 81 mph before the system failed. An observer at the airport visually observed a separate anemometer located on the rooftop reach 106 mph.  The automated system measured a sustained wind of 68 mph before failing.

  • Extensive tree and power line damage occurred in the Murphysboro, Carbondale, and Marion areas of southern Illinois and Perry and Bollinger Counties of southeast Missouri. Numerous structures were damaged in the Marion, Carbondale, and Murphysboro areas. While injuries were reported, an approximate count was not available. One fatality occurred in Jackson County when a tree fell on a home, causing an elderly man to fall to his death. 
  • State disaster declarations were granted for Jackson, Williamson, and Franklin Counties. Curfews and states of emergency were declared locally.
  • The Williamson County airport near Marion reported a peak gust of 86 mph. There was extensive damage at the airport, including hangar buildings.
  • Wind damage extended eastward into the Harrisburg area (Saline County). The system weakened before exiting southern Illinois.
  • Damage surveys were conducted on Saturday, Monday, and Tuesday.   
  • The damaging winds were associated with the "comma head" of a bow echo. The comma head maintained unusually strong intensity after the bow echo began to dissipate.

 Radar Images:

Radar image of the "eye" feature, which developed in the center of the comma head. The "eye" is visible as the light blue center surrounded by heavier echoes. This feature is located just north of Carbondale (near center of photo and due east of Farmington, MO). Image taken at 1:28 P.M. CDT.

radar image of May 8 comma head 

Radar image of the "eye-like" center, taken at 12:57 P.M. The center was over Murphysboro in this image.

radar image of eye-like center

 

Preliminary Storm Report Listing:

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE PADUCAH KY
506 PM CDT FRI MAY 08 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1025 AM     TSTM WND GST     5 E DONIPHAN            36.62N 90.73W
05/08/2009  E60.00 MPH       RIPLEY             MO   NWS EMPLOYEE

1029 AM     TSTM WND GST     DONIPHAN                36.62N 90.82W
05/08/2009  M79.00 MPH       RIPLEY             MO   COUNTY OFFICIAL

1030 AM     TSTM WND DMG     DONIPHAN                36.62N 90.82W
05/08/2009                   RIPLEY             MO   COUNTY OFFICIAL

            NUMEROUS TREES DOWN IN RIPLEY COUNTY. 2 MAIN BUILDINGS IN
            DOWNTOWN DONIPHAN LOST THEIR ROOFS. TIME ESTIMATED.

1030 AM     TSTM WND DMG     DONIPHAN                36.62N 90.82W
05/08/2009                   RIPLEY             MO   EMERGENCY MNGR

            A TRAILER HAS A TREE THROUGH IT ON COUNTY HIGHWAY Y.
            NUMEROUS POWER OUTAGES

1050 AM     TSTM WND DMG     1 S POPLAR BLUFF        36.75N 90.41W
05/08/2009                   BUTLER             MO   LAW ENFORCEMENT

            *** 2 FATAL *** MISSOURI HIGHWAY PATROL REPORTED A TREE
            FELL ON A CAR...THE CAR CAUGHT ON FIRE AND 2 PEOPLE
            INSIDE WERE KILLED. LOCATION WAS ONE MILE SOUTH OF POPLAR
            BLUFF ON HIGHWAY 53. TIME APPROXIMATE.

1130 AM     TSTM WND DMG     DONGOLA                 37.36N 89.16W
05/08/2009                   UNION              IL   EMERGENCY MNGR

            TRAILERS DAMAGED ON UNION/PULASKI COUNTY LINE. MANY TREES
            AND POWERLINES DOWN

1131 AM     FUNNEL CLOUD     PINCKNEYVILLE           38.08N 89.38W
05/08/2009                   PERRY              IL   COUNTY OFFICIAL

            COUNTY OFFICIAL REPORTED A FUNNEL CLOUD NEAR HWY 13 AND
            HWY 127...NEAR SHADY OAK ROAD. THE FUNNEL CLOUD HAS NOW
            LIFTED.

1137 AM     TORNADO          7 S PINCKNEYVILLE       37.98N 89.38W
05/08/2009                   PERRY              IL   LAW ENFORCEMENT

            TORNADO TOUCHED DOWN BRIEFLY AND WENT RIGHT BACK UP

1139 AM     HAIL             HERRIN                  37.80N 89.03W
05/08/2009  E1.75 INCH       WILLIAMSON         IL   TRAINED SPOTTER

1144 AM     HAIL             HERRIN                  37.80N 89.03W
05/08/2009  E1.75 INCH       WILLIAMSON         IL   EMERGENCY MNGR

1144 AM     HAIL             COLP                    37.81N 89.08W
05/08/2009  E1.75 INCH       WILLIAMSON         IL   LAW ENFORCEMENT

1151 AM     TORNADO          1 S RADDLE              37.76N 89.59W
05/08/2009                   JACKSON            IL   LAW ENFORCEMENT

            TORNADO ON THE GROUND IN A FIELD ON INDIAN RIDGE ROAD

1201 PM     HEAVY RAIN       MARION                  37.73N 88.94W
05/08/2009  E0.00 INCH       WILLIAMSON         IL   EMERGENCY MNGR

            PONDING OF WATER THROUGHOUT MARION. VISIBILITY OF 1 BLOCK
            AT TIMES DUE TO HEAVY RAIN

1202 PM     FLASH FLOOD      PINCKNEYVILLE           38.08N 89.38W
05/08/2009                   PERRY              IL   TRAINED SPOTTER

            WATER OVER ROADWAYS. THREE QUARTERS OF AN INCH OF
            RAINFALL IN LESS THAN THIRTY MINUTES.

1202 PM     FLASH FLOOD      MARION                  37.73N 88.94W
05/08/2009                   WILLIAMSON         IL   TRAINED SPOTTER

            REPORTED PONDING OF ROADS ACROSS THE CITY. VISIBILITY WAS
            DOWN TO ONE BLOCK.

1223 PM     FLASH FLOOD      SESSER                  38.09N 89.05W
05/08/2009                   FRANKLIN           IL   TRAINED SPOTTER

            WATER OVER ROADS IN TOWN.

1223 PM     FLASH FLOOD      DU QUOIN                38.00N 89.24W
05/08/2009                   PERRY              IL   TRAINED SPOTTER

            FLASH FLOODING ON US ROUTE 51 IN TOWN AND ON GREENSMARKET
            RD IN RURAL PERRY COUNTY.

1230 PM     TSTM WND DMG     MILLHEIM                37.62N 89.89W
05/08/2009                   PERRY              MO   LAW ENFORCEMENT

            MACHINE SHED DESTROYED

1235 PM     TSTM WND DMG     PATTON JUNCTION         37.46N 90.03W
05/08/2009                   BOLLINGER          MO   EMERGENCY MNGR

            A LOT OF STRUCTURAL DAMAGE NORTH AND SOUTH ALONG HIGHWAY
            72. ALSO...NUMEROUS TREES AND POWER LINES DOWN

1250 PM     TSTM WND DMG     OAK RIDGE               37.50N 89.73W
05/08/2009                   CAPE GIRARDEAU     MO   EMERGENCY MNGR

            NUMEROUS TREES AND POWER LINES DOWN. EMA DEPUTY DIRECTORS
            HOME HAS PANELING BLOWN OFF WALL AND WINDOWS ARE BLOWN
            OUT.

1252 PM     TSTM WND DMG     GRAND TOWER             37.64N 89.50W
05/08/2009                   JACKSON            IL   EMERGENCY MNGR

0100 PM     TSTM WND GST     GORHAM                  37.72N 89.48W
05/08/2009  E70.00 MPH       JACKSON            IL   LAW ENFORCEMENT

0112 PM     TORNADO          ELKVILLE                37.91N 89.24W
05/08/2009                   JACKSON            IL   EMERGENCY MNGR

            TORNADO REPORTED ON GROUND BY SHERIFFS DEPARTMENT
            DEPUTIES.

0120 PM     TSTM WND DMG     GRAND TOWER             37.64N 89.50W
05/08/2009                   JACKSON            IL   EMERGENCY MNGR

            WIDESPREAD WIND DAMAGE. NUMEROUS TREES...POWERLINES AND
            SOME STRUCTURAL DAMAGE IN GRAND
            TOWER...MURPHYSBORO...VERGENNES AND GORHAM

0125 PM     TSTM WND DMG     CARBONDALE              37.72N 89.22W
05/08/2009                   JACKSON            IL   EMERGENCY MNGR

            MULTIPLE INJURIES. CARBONDALE VIRTUALLY IMPASSABLE DUE TO
            DEBRIS. WIDESPREAD STRUCTURAL DAMAGE. NUMEROUS TREES AND
            POWERLINES DOWN. ROOF COLLAPSE ON ONE SCHOOL.

0125 PM     TSTM WND GST     CARBONDALE              37.72N 89.22W
05/08/2009  M106 MPH         JACKSON            IL   TRAINED SPOTTER

            MEASURED AT CARBONDALE AIRPORT BY PRIVATE BACKUP
            ANEMOMETER.

0132 PM     TSTM WND GST     DU QUOIN                38.00N 89.24W
05/08/2009  E80.00 MPH       PERRY              IL   TRAINED SPOTTER

            TREES DOWN

0138 PM     TSTM WND GST     MARION                  37.73N 88.94W
05/08/2009  E88.00 MPH       WILLIAMSON         IL   AWOS

            REPORTED AT WILLIAMSON COUNTY AIRPORT

0142 PM     TSTM WND GST     MARION                  37.73N 88.94W
05/08/2009  E82.00 MPH       WILLIAMSON         IL   TRAINED SPOTTER

            STRUCTURAL DAMAGE TO ALL BUILDINGS AT THE WILLIAMSON
            COUNTY AIRPORT

0145 PM     TSTM WND GST     ZEIGLER                 37.90N 89.05W
05/08/2009  E70.00 MPH       FRANKLIN           IL   TRAINED SPOTTER

0147 PM     TSTM WND GST     CARTERVILLE             37.76N 89.08W
05/08/2009  E80.00 MPH       WILLIAMSON         IL   BROADCAST MEDIA

            TV STATION OFF THE AIR WITH STRUCTURAL AND ROOF DAMAGE.
            NUMEROUS TREES DOWN

0150 PM     TSTM WND GST     HOPKINSVILLE            36.85N 87.49W
05/08/2009  E75.00 MPH       CHRISTIAN          KY   TRAINED SPOTTER

            AT WESTERN STATE HOSPITAL

0215 PM     TSTM WND DMG     GALATIA                 37.84N 88.61W
05/08/2009                   SALINE             IL   TRAINED SPOTTER

            MANY TREES AND POWERLINES DOWN

0215 PM     TSTM WND GST     HARRISBURG              37.74N 88.55W
05/08/2009  E90.00 MPH       SALINE             IL   LAW ENFORCEMENT

0230 PM     FLASH FLOOD      GREENVILLE              37.21N 87.18W
05/08/2009                   MUHLENBERG         KY   PUBLIC

            THREE TO FOUR FEET OF WATER FLOODED A FARM AND HORSES HAD
            TO EVACUATED.

0230 PM     FLASH FLOOD      CALHOUN                 37.54N 87.26W
05/08/2009                   MCLEAN             KY   EMERGENCY MNGR

            WATER OVER MANY ROADS ALONG HIGHWAY 136

0230 PM     FLASH FLOOD      CENTRAL CITY            37.30N 87.13W
05/08/2009                   MUHLENBERG         KY   EMERGENCY MNGR

            MANY ROADS FLOODED IN POWDERLY AND CENTRAL CITY

0230 PM     FLASH FLOOD      DU QUOIN                38.00N 89.24W
05/08/2009                   PERRY              IL   EMERGENCY MNGR

            MANY RURAL ROADS ARE CLOSED DUE TO HIGH WATER

0245 PM     FLASH FLOOD      BENTON                  38.01N 88.92W
05/08/2009                   FRANKLIN           IL   EMERGENCY MNGR

            WIDESPREAD FLOODING ACROSS MANY COUNTY ROADS

0245 PM     FLASH FLOOD      MOUNT VERNON            38.32N 88.91W
05/08/2009                   JEFFERSON          IL   DEPT OF HIGHWAYS

            HIGH WATER ACROSS MANY COUNTY ROADS

0253 PM     TSTM WND DMG     HARRISBURG              37.74N 88.55W
05/08/2009                   SALINE             IL   LAW ENFORCEMENT

            NUMEROUS TREES AND POWER LINES DOWN IN HARRISBURG,
            ELDORADO, CARRIER MILLS, GALATIA AND RALEIGH. TREE FELL
            ON HOUSE AND STRUCK GAS METER...GAS LEAKING IN GALATIA.
            ROOF BLOWN OFF BUILDING IN CARRIER MILLS AND STRUCK GAS
            METER...GAS LEAKING. TREE FELL ON PROPANE TANK IN
            STONEFORT...GAS LEAKING. SEMI BLOWN OVER ON IL 34 NEAR
            HARRISBURG AIRPORT. DEPUTY REPORTED ESTIMATED 90 MPH
            WINDS NEAR HARCO WITH DEBRIS IN THE AIR. IL 34 CLOSED IN
            NUMEROUS LOCATIONS.PORTIONS OF US45 CLOSED NEAR LEDFORD.

0300 PM     FLASH FLOOD      POSEYVILLE              38.17N 87.78W
05/08/2009                   POSEY              IN   TRAINED SPOTTER

            RUNNING WATER OVER MOST ROADWAYS

0315 PM     FLASH FLOOD      EVANSVILLE              37.98N 87.54W
05/08/2009                   VANDERBURGH        IN   EMERGENCY MNGR

            SEVERAL ROADS CLOSED WITH WATER RISING. WATER RESCUES ARE
            BEING PERFORMED

0414 PM     FLASH FLOOD      5 SE EVANSVILLE         37.93N 87.48W
05/08/2009                   VANDERBURGH        IN   TRAINED SPOTTER

            15 HOUR STORM TOTAL OF THREE INCHES AT ANGEL MOUNDS. THIS
            REULTED IN EXTENSIVE FLOODING AND WATER RESCUES.


 Tornado Damage Surveys

Photo of a brief tornado touchdown just north of Royalton, IL (Franklin Co.), courtesy of Ryan Buckingham. Leaves were observed in the rotation. This was a brief EF-0 tornado.

 Photo of tornado just north of Royalton

 


 

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE PADUCAH KY
434 PM CDT TUE MAY 12 2009

...DAMAGE SURVEY RESULTS FOR TORNADO EVENT IN SOUTHERN ILLINOIS...

THE FOLLOWING IS THE DAMAGE ASSESSMENT FOR A TORNADO THAT
OCCURRED FRIDAY MAY 8TH 2009 IN SOUTHERN ILLINOIS...IN FRANKLIN
AND WILLIAMSON COUNTIES.

* EVENT DATE - FRIDAY MAY 8 2009

* EVENT TIME - APPROXIMATELY 245 PM TO 250 PM CDT

* EVENT TYPE - EF1 TORNADO

* EVENT LOCATION - FROM 2 MILES SOUTH OF THOMPSONVILLE TO 7 MILES
                   NORTHEAST OF CRAB ORCHARD

* PEAK WIND - 90 MPH

* AVERAGE PATH WIDTH - 150 YARDS

* PATH LENGTH - 5 MILES

* INJURIES - NONE

* FATALITIES - NONE

* DISCUSSION/DAMAGE...A SWATH OF DOWNED TREES WAS FOUND IN RURAL
                      AREAS

SURVEYORS...SHANKLIN/SPODEN

$$

MAP of Franklin/Williamson County Tornado

Path map of Franklin/Williamson County tornado

Photo of tree damage south of Thompsonville:

Tree damage near Thompsonville


PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE PADUCAH KY
746 PM CDT SAT MAY 9 2009


...DAMAGE SURVEY RESULTS FOR A TORNADO TOUCHDOWN IN NORTHERN
JACKSON COUNTY ILLINOIS ON MAY 8TH 2009...

THE FOLLOWING IS THE DAMAGE ASSESSMENT FOR A TORNADO TOUCHDOWN
THAT OCCURRED FRIDAY MORNING...MAY 8TH 2009...IN NORTHERN JACKSON
COUNTY ILLINOIS.

* EVENT DATE - FRIDAY MAY 8 2009

* EVENT TIME - APPROXIMATELY 11:30 AM CDT

* EVENT TYPE - EF1 TORNADO

* EVENT LOCATION - NORTHERN JACKSON COUNTY...FROM 10 WSW DU QUOIN
  TO 7 WSW DU QUOIN...RIGHT ON THE JACKSON IL/PERRY IL COUNTY
  BORDER.

* PEAK WIND - 95 MPH

* AVERAGE PATH WIDTH - 100 YARDS

* PATH LENGTH - 3 MILES

* INJURIES - NONE

* FATALITIES - NONE

* DISCUSSION/DAMAGE - DOZENS OF LARGE TREES SNAPPED AND UPROOTED.
STRUCTURAL DAMAGE TO TWO BARNS WITH METAL ROOF PANELS AND METAL
DOORS BLOWN OFF. SHINGLES BLOWN OFF SEVERAL HOMES. SEVERAL POWER
POLES BLOWN OVER, ONE SNAPPED OFF. MOST OF TORNADO PATH WAS THROUGH
OPEN FIELDS.

$$

SURVEYORS...HOOPER/BLANCHARD


PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE PADUCAH KY
343 PM CDT MON MAY 11 2009

...DAMAGE SURVEY RESULTS FOR A TORNADO TOUCHDOWN IN NORTHERN
PERRY COUNTY MISSOURI ON MAY 8TH 2009...

THE FOLLOWING IS THE DAMAGE ASSESSMENT FOR A TORNADO TOUCHDOWN
THAT OCCURRED FRIDAY MORNING...MAY 8TH 2009...IN NORTHERN PERRY COUNTY
MISSOURI.

* EVENT DATE - FRIDAY MAY 8 2009

* EVENT TIME - UNKNOWN...POSSIBLY 11:20 AM CDT BASED ON RADAR

* EVENT TYPE - EF0 TORNADO

* EVENT LOCATION - NORTHERN PERRY COUNTY...FROM 2.2 MILES WEST OF
  MCBRIDE TO MCBRIDE

* PEAK WIND - 65 MPH

* AVERAGE PATH WIDTH - 50 YARDS

* PATH LENGTH - 2.2 MILES

* INJURIES - NONE

* FATALITIES - NONE

* DISCUSSION/DAMAGE... VIDEOTAPED BY PERSON AT THE PERRYVILLE
  AIRPORT AND SHOWN ON LOCAL MEDIA OUTLET. PATH VISIBLE IN WHEAT
  FIELD ALONG COUNTY ROAD 934. DOZENS OF TREES DOWN NEAR THE
  PATH...APPARENTLY DUE TO INFLOW WINDS. EYEWITNESS ACCOUNTS.

SURVEYORS...HOOPER/BLANCHARD


PHOTOS
Straight-line winds along Route 13 in Marion/Carbondale area:

Numerous signs were damaged...

sign damage at Marion

Many towers were bent...

bent tower in Marion area

Signs were blown out...

sign blown out

This gas station's canopy over the pumps was levelled...

gas station canopy destroyed

Tree on house in Murphysboro...

tree on house in Murphysboro

Tree on house at Galatia, IL (photo from Saline Co. 911):

Tree on house at Galatia, IL

One of many utility poles down on Route 13 between Marion and Carbondale:

Utility pole down on Route 13

Traffic lights were out at major intersections along Route 13:

Traffic light out on Route 13

Mobile home heavily damaged in rural northeast Jackson County:

Mobile home heavily damaged in rural Jackson County, IL

Trees down across Interstate 57 near the 60-mile marker in far northern Williamson County (photo courtesy Stephen Hagan):

Trees on Interstate 57

Semis were overturned on Interstate 57 (photo courtesy of Stephen Hagan):

overturned semi on I-57

Building heavily damaged in Carrier Mills, IL (Saline County):

damaged building in Carrier Mills, IL

Home under construction blown down in southern Williamson County, south of Marion:

Home under construction blown down



Map

Map of peak winds on May 8, 2009

 

 


There have been windstorms similar to this in the past. On July 22, 1980, a similar windstorm moved through the region with damaging winds over 100 mph.This derecho was actually the storm system that sparked the study on these types of windstorms and where the term "derecho" originated.

Below is a sketch of the location of the leading edge of the derecho. thanks for Bob Johns

 image of derecho leading edge in 1980

The surface map looked like this...

surafce map from July 22, 1980

The morning radar image...

difax radar image of July 22, 1980

Here are copies of storm data submitted from this storm

storm data from July 1980

second image of storm data for July 1980

 

 


 



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