Tornado and Flash Flooding in Missouri, August 20, 2007

Name: Tornado and Flash Flooding in Missouri, August 20, 2007
Start: 2007-08-20T04:30
End: 2007-08-20T20:00
Location: Missouri

August 20, 2007 · NWS SGF · 13 events in 11 counties and zones

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 1
Injuries: 0
Property damage: $22 million
Crop damage: None recorded
Events: 13

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS SGF wrote it up.

The remnants of Tropical Storm Erin produced significant flash flooding along a line from northern Jasper County to northern Laclede County. Numerous roads were washed out across Lawrence, Greene, Polk, Dallas, and Webster counties. This prompted several water rescues. One man was killed in Laclede County as he attempted to cross a section of a road that had been washed out from flood water.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Springfield, MO wrote its last area forecast discussion before the first event at Aug 20, 1:57 AM CST, 2 hours 33 minutes earlier.

Area forecast discussion, Aug 20, 1:57 AM CST, 2 hours 33 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
257 AM CDT MON AUG 20 2007

.DISCUSSION...

MAIN FORECAST CONCERN IS HEAVY RAIN POTENTIAL TODAY AS THE
REMNANTS OF ERIN FINALLY LEAVE THE OZARKS. SLIGHT CONCERN FOR
TONIGHT WITH A POTENTIAL MCS TRACKING SOUTH AND SOUTHEAST TOWARDS
THE OZARKS. ATTENTION THEN TURNS TO TEMPERATURES FOR MIDWEEK AS
HIGHS GET BACK INTO THE 90S. WILL THEN LOOK AT A SLIGHT SHIFT IN
THE UPPER LEVEL PATTERN AND ITS IMPLICATIONS FOR THE OZARKS LATE
THIS WEEK.

TODAY...A RECENT BLOSSOM IN RADAR REFLECTIVITIES OVERNIGHT IS
LIKELY BEING AIDED BY A POCKET OF ISENTROPIC UPGLIDE OWING TO A 40
TO 45 KNOT LOW LEVEL JET. THIS FEATURE IS EXPECTED TO SLOWLY
TRANSLATE NORTHEASTWARD ALONG THE INTERSTATE 44 CORRIDOR EARLY
THIS MORNING AND WEAKEN...AS THE UPPER LEVEL WAVE LEFT FROM ERIN
SHEARS EAST. THEREFORE THINK THE MAIN HEAVY RAIN THREAT WILL BE
EARLY THIS MORNING. TROPICAL AIRMASS AND HIGH FREEZING LEVELS
STILL SUPPORT A HEAVY RAIN POTENTIAL THROUGH THE AFTERNOON...
JUST WILL NOT BE AS WIDESPREAD. WILL THEREFORE KEEP THE FLASH
FLOOD WATCH GOING THROUGH 15Z. DAY SHIFT MAY NEED TO EXTEND THE
NORTHEAST PORTION OF THE WATCH...BUT AM NOT GOING TO GET TOO CUTE
RIGHT NOW. RAIN WILL COME TO AN END OVER SOUTHEAST KANSAS AND
SOUTHWEST MISSOURI BY LATE THIS AFTERNOON AS THE UPPER LEVEL WAVE
SHIFTS INTO THE OHIO RIVER VALLEY. DID NOT STRAY TOO FAR FROM MAV
TEMPERATURES...BUT DID KNOCK THEM DOWN A BIT OVER CENTRAL MISSOURI
WITH THE EXPECTED RAIN AND CLOUD COVER.

TONIGHT...SHOULD BE FAIRLY QUITE OVER MOST OF THE OZARKS. COULD
SEE A REMAINING SHOWER OR TWO UP TOWARDS VICHY THIS EVENING. A
LITTLE BIT OF CONCERN FOR SOME FOG DEVELOPMENT GIVEN THE RECENT
RAINFALL. PRESSURE GRADIENTS AT THE SURFACE SHOULD BE TIGHT ENOUGH
TO KEEP WINDS IN THE 5 TO 10 KNOT RANGE OVER MOST AREAS...WITH THE
ONE EXCEPTION POSSIBLY BEING SOUTH CENTRAL MISSOURI. MAY SEE
VISIBILITIES DROP A BIT AFTER MIDNIGHT...BUT NOT THINKING DENSE
FOG AT THIS TIME. EYES THEN TURN NORTH AS AN MCS IS EXPECTED TO
DEVELOP SOMEWHERE UP IN THE CORN BELT. THIS MCS WOULD LIKELY TRACK
SOUTH TO SOUTHEAST AND AFFECT PORTIONS OF NORTHEAST KANSAS AND
NORTHWEST MISSOURI LATE TONIGHT. WITH THE LACK OF A DECENT LOW
LEVEL JET...NOT SURE IT WILL MAKE IT INTO SOUTHEAST KANSAS AND
CENTRAL MISSOURI. PLACED SLIGHT CHANCE POPS TO COVER THIS FOR NOW
AND WILL LET LATER SHIFTS CONTINUE TO EVALUATE.

TUESDAY THROUGH WEDNESDAY NIGHT...SLOW HEIGHT RISES WILL LEAD TO A
WARMING AND DRYING TREND. WILL STILL NEED TO WATCH THE EVOLUTION
OF THAT MCS TUESDAY MORNING. VERY WELL POSSIBLE THERE COULD BE
SOME KIND OF OUTFLOW BOUNDARIES TO DEAL WITH LATER TUESDAY
SOMEWHERE ACROSS CENTRAL MISSOURI. AS OF RIGHT NOW...THINK CAP
WILL HOLD AND MOST AREAS WILL BE DRY. HOWEVER...DECENT CONVERGENCE
ALONG AN OUTFLOW BOUNDARY MAY BE ENOUGH TO GET SOMETHING GOING.
KEPT POPS BELOW 15 PERCENT FOR NOW. OTHERWISE...850 MB
TEMPERATURES WARMING INTO THE LOWER 20S CELSIUS SPELL LOWER TO
MIDDLE 90S FOR HIGHS.

THURSDAY THROUGH SUNDAY...HEIGHTS WILL LOWER ACROSS THE NORTHERN
TIER OF STATES. THE PATTERN LOOKS AMPLIFIED ENOUGH TO EVENTUALLY
SUPPORT A FRONT MAKING IT DOWN INTO THE OZARKS. TIME FRAME FOR A
FRONTAL PASSAGE RIGHT NOW IS SOMETIME ON FRIDAY OR SATURDAY.
SLIGHT CHANCE TO CHANCE POPS WERE BRACKETED AROUND THIS PERIOD.
TEMPERATURES WILL STAY WARM AHEAD OF THE FRONT WITH HIGHS STILL IN
THE LOWER TO MIDDLE 90S THURSDAY AND POSSIBLY FRIDAY. WILL THEN
NEED TO SEE WHERE THAT FRONT ENDS UP NEXT WEEKEND TO GET A BETTER
HANDLE ON POPS AND TEMPERATURES.

SCHAUMANN

&&

.AVIATION...

FOR THE 06Z TAF PACKAGE...BANDS OF SHRA CONTINUE TO DEVELOP ACROSS
THE REGION. BETTER COVERAGE HAS DEVELOP DURING THE PAST HOUR NEAR
THE MO/KS BORDER AND THIS TREND SHOULD CONTINUE OVER THE NEXT FEW
HOURS. THE JLN AND SGF AERODROMES WILL EXPERIENCE OCCASIONAL BOUTS
OF MODERATE TO HEAVY RAINFALL WITH ON AGAIN OFF AGAIN MVFR/IFR CIG
AND VIS. THE UPPER WAVE RESPONSIBLE FOR THIS ACTIVITY WILL SLOWLY
BUT DELIBERATELY SPREAD TO THE EAST AND CLEARING CONDITIONS ARE
EXPECTED FROM MIDDAY ONWARD. OCCASIONALLY GUSTY WINDS ARE EXPECTED
THROUGH THE MORNING HOURS.

GAGAN

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR MOZ055>058-
     068>070-078>081-088>095-101>104.

KS...NONE.
&&

Hazardous weather outlook, Aug 19, 6:59 PM CST, 9 hours 31 minutes before

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE SPRINGFIELD MO
759 PM CDT SUN AUG 19 2007

KSZ073-097-101-MOZ055>058-066>071-077>083-088>098-101>106-210100-
BOURBON-CRAWFORD-CHEROKEE-BENTON-MORGAN-MILLER-MARIES-VERNON-
ST. CLAIR-HICKORY-CAMDEN-PULASKI-PHELPS-BARTON-CEDAR-POLK-DALLAS-
LACLEDE-TEXAS-DENT-JASPER-DADE-GREENE-WEBSTER-WRIGHT-NEWTON-
LAWRENCE-CHRISTIAN-DOUGLAS-HOWELL-SHANNON-MCDONALD-BARRY-STONE-
TANEY-OZARK-OREGON-
759 PM CDT SUN AUG 19 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF THE MISSOURI
OZARKS AND EXTREME SOUTHEAST KANSAS.

.DAY ONE...TONIGHT.

 SHOWERS AND THUNDERSTORMS CAN BE EXPECTED ACROSS THE OUTLOOK
 AREA THROUGH TONIGHT AS THE REMNANTS OF TROPICAL STORM ERIN MOVE
 ACROSS THE OZARKS REGION.

 LIMITED INSTABILITY WILL LIMIT THE POTENTIAL FOR SEVERE WEATHER.
 HOWEVER WIND GUSTS TO 50 MPH WILL BE POSSIBLE IN THE STRONGEST
 STORMS.

 LOCALLY HEAVY RAINFALL WILL BE POSSIBLE ALONG WITH THE POTENTIAL
 OF LOCALIZED FLASH FLOODING.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

 ADDITIONAL THUNDERSTORMS WILL BE POSSIBLE ON MONDAY AND TUESDAY.
 THESE THUNDERSTORMS WILL BE MORE FREQUENT DURING THE AFTERNOON
 PERIODS...WHEN MAXIMUM ATMOSPHERIC DESTABILIZATION OCCURS DUE
 TO DAYTIME HEATING. LOCALIZED AREAS OF FLASH FLOODING ALONG WITH
 A FEW MICROBURSTS CAN NOT BE RULED OUT.

 AFTERNOON HEAT INDEX VALUES GREATER THAN 100 DEGREES WILL BE
 POSSIBLE FROM TUESDAY THROUGH FRIDAY ACROSS PORTIONS OF WESTERN
 AND SOUTH CENTRAL MISSOURI...AS WELL AS EXTREME SOUTHEAST
 KANSAS.

.SPOTTER INFORMATION STATEMENT...

 SPOTTER ACTIVATION WILL NOT BE NEEDED THROUGH TONIGHT. PLEASE
 FORWARD ANY REPORTS OF HEAVY RAINFALL AND FLOODING TO LOCAL LAW
 ENFORCEMENT OR THE NATIONAL WEATHER SERVICE IN SPRINGFIELD
 MISSOURI.

&&

THIS PRODUCT IS NOW AVAILABLE IN GRAPHICAL FORMAT...ALONG WITH
OTHER WEATHER...HYDROLOGICAL AND CLIMATE INFORMATION...AT
HTTP://WWW.CRH.NOAA.GOV/SGF(ALL LOWERCASE)

GAGAN

The radar

The Springfield radar (KSGF), 65 km away, was scanning. The volume nearest the first event began at 10:28 UTC.

Open the radar archive at this moment

Event by event

10 flash flood, 2 thunderstorm wind, 1 tornado. Local standard time, as filed.

Flash Flood, Jasper

When: August 20, 4:30 AM CST to 3:00 PM CST
Where: Jasper County, Avilla
Cause: Heavy Rain
Reported by: Law Enforcement
Coordinates: 37.200, -94.130

The remnants of Tropical Storm Erin caused flash flooding in several areas of eastern Jasper County. Low lying areas and roads experienced flooding for several hours prior to receding to below flood status later that afternoon. Specific locations where flooding was observed include, a section of Highway 96 near Avilla, a section of Highway 37 south of Avilla, and several other county roads in eastern Jasper County.

Flash Flood, Lawrence

When: August 20, 5:40 AM CST to 3:00 PM CST
Where: Lawrence County, 0.88 mi SE of Miller
Cause: Heavy Rain
Property damage: $2.5 million
Reported by: Public
Coordinates: 37.211, -93.839

Volunteer observations near the community of Miller measured nearly 12 inches of rain during the early morning hours as the remnants of Tropical Storm Erin passed over the county. Very serious flash flooding resulted in numerous water rescues across northern sections of the county. Several roads and low water bridges were washed out.

Flash Flood, Dade

When: August 20, 6:00 AM CST to 2:00 PM CST
Where: Dade County, 2.35 mi SSE of Pennsboro
Cause: Heavy Rain
Property damage: $2.3 million
Reported by: Law Enforcement
Coordinates: 37.299, -93.834

The remnants of Tropical Storm Erin caused flash flooding across central and southern sections of Dade County. Locations that flooded include sections of Highway 39 near Pennsboro and north of Greenfield, a section of County Road NN near the Dade and Lawrence county line, a section of Highway 97 south of Lockwood, several sections of Highway K between Pennsboro and Everton, a section of Highway 160 near its intersection with Highway 245, a section of Highway O just east of its intersection with Highway 160, and a section of Highway U east of its intersection with Highway 245.

Flash Flood, Greene

When: August 20, 7:40 AM CST to 3:00 PM CST
Where: Greene County, 0.69 mi S of Walnut Grove
Cause: Heavy Rain
Property damage: $2.0 million
Reported by: Public
Coordinates: 37.410, -93.550

Excessive rainfall associated with the remnants of Tropical Storm Erin impacted northern Greene County. Numerous roads and low water crossings were washed out and had to be fully repaired. Flooding also impacted a bank in Walnut Grove. Specific locations that were impacted include, hundreds of sections of secondary roads across northern Greene County, a section there Route V between Highway 160 and Route BB, and numerous sections of Highway 123 between Walnut Grove and Willard.

Flash Flood, Polk

When: August 20, 7:40 AM CST to 3:00 PM CST
Where: Polk County, 0.55 mi W of Eudora
Cause: Heavy Rain
Property damage: $9.0 million
Reported by: County Official
Coordinates: 37.480, -93.560

The remnants of Tropical Storm Erin caused serious flooding across southern and central Polk County. Numerous secondary roads were washed out along with many low water crossings. Specific locations that were flooded include a bridge on Highway W near its intersection with Highway 123, a section of Highway 215 west of Eudora where the Turkey Creek intersects the highway, a section Highway 123 south of Eudora, a few streets in the city of Bolivar, a section of Highway 13 near the Polk and Greene county Line experienced 5 feet of flash flood water, all roads leading in and out of Pleasant Hope became impassable, and areas of Pleasant Hope flooded with a few houses impacted.

Flash Flood, Webster

When: August 20, 9:45 AM CST to 3:00 PM CST
Where: Webster County, 0.88 mi NE of Marshfield
Cause: Heavy Rain
Property damage: $600,000
Reported by: Emergency Manager
Coordinates: 37.339, -92.909

Excessive rainfall from Tropical Storm Erin continued across much of Webster County. This caused flash flooding on a section of Highway 38 nears its junction of Highway J, a section of Route DD near the Marshfield High School, a section of Evans Road, a bridge washed out on Route DD from flash flooding of the Osage Fork River, and a section of Highway A near its intersection with Highway FF.

Flash Flood, Dallas

When: August 20, 10:51 AM CST to 3:00 PM CST
Where: Dallas County, 0.88 mi SE of Buffalo
Cause: Heavy Rain
Property damage: $50,000
Reported by: Law Enforcement
Coordinates: 37.641, -93.089

The remnants of Tropical Storm Erin produced excessive rainfall across much of Dallas County. Flash flooding of low lying areas and roads occurred. Specific locations that experienced flooding include a section of Highway 65 in Buffalo between its intersection with Highway 32 and W Highway, a low water crossing between Rocket Road and Rainbow Road, and a section of Highway 73 north of Rainbow Road.

Flash Flood, Laclede

When: August 20, 11:25 AM CST to 8:00 PM CST
Where: Laclede County, 0.55 mi E of Lebanon
Cause: Heavy Rain
Deaths: 1 direct, 0 indirect
Property damage: $5.5 million
Reported by: Emergency Manager
Coordinates: 37.680, -92.660

Tropical Storm Erin remnants impacted areas of Laclede County. Flash flooding occurred county wide causing road closures to a section of Highway 32 near Pinetree Road, West Elm Road between Drury Road and Springfield Road, a section of Route BB northwest of Sleeper and north of Route F, the intersection of Highway 32 and Highway K, the intersection of Route BB and Highway F, the intersection of Route T and Highway FF, the outer road of interstate 44 at Route N, and a section of a secondary road near Sleeper. A United State Postal employee delivering rural mail drove into a washed out bridge and was swept away by flood water.

Thunderstorm Wind, Laclede

When: August 20, 1:15 PM CST
Where: Laclede County, 5 mi SW of Falcon
Measured: 50 kt (58 mph) estimated gust
Reported by: Public
Coordinates: 37.549, -92.445

Severe thunderstorm wind gusts downed a few trees near Nebo.

Thunderstorm Wind, Laclede

When: August 20, 1:40 PM CST
Where: Laclede County, 2 mi W of Lynchburg
Measured: 50 kt (58 mph) estimated gust
Reported by: Public
Coordinates: 37.500, -92.337

Severe thunderstorm wind gusts downed a few trees west of Lynchburg.

Tornado, Texas

When: August 20, 1:45 PM CST to 1:46 PM CST
Where: Texas County, 3 mi E of Roby
Rating: EF0
Path length: 0.1 mi
Path width: 50 yd
Reported by: Public
Coordinates: 37.520, -92.095

A National Weather Service storm survey revealed that an EF-0 tornado briefly touched down in a rural area three miles east of Roby. A few trees experienced minor damage.

Flash Flood, Camden

When: August 20, 1:46 PM CST to 4:00 PM CST
Where: Camden County, 0.55 mi W of Stoutland
Cause: Heavy Rain
Reported by: Law Enforcement
Coordinates: 37.820, -92.530

Heavy rain from the remnants of Tropical Storm Erin caused flooding across a few areas of Camden County. Locations that experienced flooding include low water crossings on Route BB just south of Highway 7, a section of Route H west of Route T, and numerous low water crossings across southern sections of the county.

Flash Flood, Pulaski

When: August 20, 4:26 PM CST to 5:45 PM CST
Where: Pulaski County, 3.89 mi NW of Devils Elbow
Cause: Heavy Rain
Reported by: Fire Department/Rescue
Coordinates: 37.890, -92.120

The Gasconade River rapidly flooded areas near the Gasconade Hills Resort from excessive rainfall associated with Tropical Storm Erin. A section of Route H two miles south of Interstate 44.

The people who died

As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.

Event	Date	Age	Sex	Where	Kind
Flash Flood, Laclede	2007-08-20	51	Male	Vehicle/Towed Trailer	Direct

What these are

Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
Tornado: A violently rotating column of air in contact with the ground and extending from a thunderstorm, filed with its path, width and Fujita or Enhanced Fujita rating from the damage survey.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Missouri in 2007 Every state in 2007 This day in weather history The tornado archive for Missouri, 2007 Warnings in Missouri, August 2007

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 54040, 54041, 54042, 54043, 54046, 54047, 54048, 54052, 54059, 54060, 54058, 54056, 54057.