A thunderstorm produced a brief tornado which was observed moving over plowed fields.
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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.
The episode as NWS FSD wrote it up.
A thunderstorm produced a brief tornado which was observed moving over plowed fields.
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 Sioux Falls, SD wrote its last area forecast discussion before the first event at May 8, 11:40 AM CST, 1 hour earlier.
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 1240 PM CDT FRI MAY 8 2009 .DISCUSSION... VIGOROUS UPPER WAVE CURRENTLY MOVG INTO THE WRN PLAINS WL DOMINATE THIS AREAS WX THIS AFTERNOON...COUPLED WITH VERY COLD TEMPS ALOFT. GENERAL TREND OF THE FCST IS GOING GOOD...WITH OCNL RAINFALL IN THIS FA THIS AFTERNOON...WITH LESS POPS IN OUR FAR SOUTH WHERE A BIT OVERALL DRY AIRMASS EXISTS. HOWEVER WE ARE IN A SLGT RISK OF SVR TS THIS AFTERNOON AS THE SFC CDFNT/WEAK INVERTED TROF MOVES EWD THRU THAT AREA. BEST HEATING AND INSTABILITY IS OCCURRING ALONG AND SE OF A SIOUX CITY IA TO SPENCER IA LINE...WHICH COULD PRODUCE SOME HAILERS AND BRIEF HEFTY WIND GUSTS. IN OUR SW...OCNL RAIN WL DRY UP IN THOSE AREAS FIRST BUT COULD LINGER INTO THE EARLY EVENING HRS. ALTERED A FEW HIGHS TODAY BASED ON CURRENT TRENDS BUT NOTHING TOO RADICAL. /MJF && .AVIATION... OVERALL CONFIDENCE IN THE DETAILS OF THE TAFS COULD BE BETTER THIS GO AROUND. ATTM...CONDS ARE PRIMARILY VFR IN THIS FSD FA. THERE IS A WEAK INVERTED SFC TROF BISECTING THIS AREA FM NW TO SE...ALONG ROUGHLY ALONG A KHON...TO KFSD TO JUST E OF KSUX LINE. THIS TROUGH WL PULL EWD THIS AFTERNOON AS A CDFNT WITH A STRONG VIGOROUS WAVE AND VERY COLD TEMPS ALOFT FOR THIS TIME OF YEAR. THEREFORE OCNL SHRA IS A THREAT THIS AFTN WITH THE BEST CHCS FOR TS IN NW IA WHERE CONDS ARE MORE UNSTABLE. THE NAM RH TIME SECTIONS ARE STILL VERY BULLISH ON BRINGING DOWN MVFR TYPE STRATUS FM THE NORTH INTO THIS AREA... DRAINING DOWN FM NW TO SE...BASICALLY ENCOMPASSING FM VERY LATE THIS AFTERNOON THROUGH THE OVERNIGHT HRS. THE GFS RH TIME SECTIONS ARE MUCH MORE DRY IN THE LOW LEVELS. THE IFR STRATUS TO OUR NW AND N IS CURRENTLY HARD TO IGNORE...THEREFORE CONTINUED THE HEDGED TREND OF PLACING A GOOD PORTION OF OUR FA IN MVFR CIGS THROUGH THE OVERNIGHT HRS BEGINNING LATE THIS AFTERNOON OR EVENING. FOR NOW...DID NOT WANT TO LOWER THE CIGS DOWN INTO THE IFR RANGE AS THAT DEGREE OF LOW LEVEL MOISTURE MAY NOT MAKE IT THIS FAR SOUTH INTO OUR AREA. AFTER THAT...THE RH TIME SECTIONS DO DRY OUT. SO IN GENERAL...WIND SPEEDS AND DIRECTIONS ARE TRICKY IN THE SHORT TERM WITH THE PASSAGE OF THE CDFNT/INVERTED TROF...AND MVFR CIGS MAY OCCUR FM VERY LATE AFTERNOON TROUGH THE OVERNIGHT HRS...WHICH AGAIN IS NOT A FULL CERTAINTY. /MJF && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SIOUX FALLS SD 1154 AM CDT FRI MAY 08 2009 SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098- IAZ001>003-012>014-020>022-031-032-NEZ013-014-091200- AURORA-BEADLE-BON HOMME-BROOKINGS-BRULE-BUENA VISTA IA- CHARLES MIX-CHEROKEE IA-CLAY-CLAY IA-COTTONWOOD MN-DAKOTA NE- DAVISON-DICKINSON IA-DIXON NE-DOUGLAS-GREGORY-HANSON-HUTCHINSON- IDA IA-JACKSON MN-JERAULD-KINGSBURY-LAKE-LINCOLN-LINCOLN MN- LYON IA-LYON MN-MCCOOK-MINER-MINNEHAHA-MOODY-MURRAY MN-NOBLES MN- OBRIEN IA-OSCEOLA IA-PIPESTONE MN-PLYMOUTH IA-ROCK MN-SANBORN- SIOUX IA-TURNER-UNION-WOODBURY IA-YANKTON- 1154 AM CDT FRI MAY 08 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST SOUTH DAKOTA... SOUTHWEST MINNESOTA...NORTHWEST IOWA...AND NORTHEAST NEBRASKA. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS... WITH A COLD FRONT PASSAGE THIS AFTERNOON AND COLD TEMPERATURES ALOFT...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON ALONG AND SOUTHEAST OF A SIOUX CITY IOWA TO SPENCER IOWA LINE. THE MAIN THREAT WOULD BE WIND GUSTS AROUND 60 MPH AND ISOLATED HAIL UP TO THE SIZE OF QUARTERS TO HALF DOLLARS. THUNDERSTORM ACTIVITY SHOULD BE NON SEVERE ELSEWHERE. FLOODING... FLOODING WILL CONTINUE ALONG THE JAMES RIVER THROUGH MOST OF MAY. THE RIVER WAS NEAR CREST AT ALL LOCATIONS FROM HURON SOUTHWARD...AND IN FACT WAS SLIGHTLY FALLING FROM HURON TO MITCHELL. PLEASE SEE THE LATEST ISSUED FLOOD STATEMENTS FOR MORE DETAILED INFORMATION. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THERE IS THE CHANCE OF A FEW SEVERE OR HEAVY STORMS IN THE AREA LATE TUESDAY AFTERNOON AND TUESDAY NIGHT AS A COLD FRONT MOVES THROUGH. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL POSSIBLE THIS AFTERNOON ALONG AND SOUTHEAST OF A SIOUX CITY TO SPENCER IOWA LINE. && FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT WWW.WEATHER.GOV/SIOUXFALLS. THIS INCLUDES THE GRAPHICAL HAZARDOUS WEATHER OUTLOOK.
The Sioux Falls radar (KFSD), 153 km away, was scanning. The volume nearest the first event began at 18:42 UTC.
1 tornado. Local standard time, as filed.
A small tornado was observed moving across a plowed field.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2009Every state in 2009This day in weather historyThe tornado archive for Iowa, 2009Warnings in Iowa, May 2009
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: 173251.