The combination of saturated ground and heavy rain caused flash flooding of numerous roads and other low areas during the late afternoon and early evening of July 5th.
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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.
The combination of saturated ground and heavy rain caused flash flooding of numerous roads and other low areas during the late afternoon and early evening of July 5th.
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 Jul 5, 2:00 PM CST, 2 hours 10 minutes earlier.
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 300 PM CDT MON JUL 5 2010 .DISCUSSION... SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING PRETTY MUCH AS EXPECTED...JUST A BIT MORE COVERAGE. EVERY CELL HAS DISPLAYED ATTRIBUTES OF HEAVY RAINERS VERSUS HAILERS WITH MOST IF NOT ALL OF THE 50+ DBZ FOUND BELOW 20 KFT. FREEZING LEVEL AROUND 15 KFT. HAVE ALSO HAD REPORTS OF A FEW FUNNEL CLOUDS FROM DEVELOPING CELLS AND THIS SEEMS TO MAKE SENSE WITH A SFC TO 3KM CAPE AROUND 150 J/KG AND A WEAK AXIS OF VORTICITY FROM NW IA INTO SW MN. THE SHALLOW AND DEEP LAYER SHEAR IS VERY WEAK SO DO NOT EXPECT ANY OF THESE FUNNELS TO DEVELOP INTO TORNADOES. A COUPLE OF THE CELLS HAVE DISPLAYED A WEAK ROTATIONAL COUPLET WITH THEM IN THE LOW LEVELS BUT NOTHING WORTH WARNING ON. SO...WILL KEEP MID RANGE POPS IN PLACE THROUGH THE AFTERNOON AND EVENING OVER THE SOUTHEAST TWO THIRDS OF THE CWA WITH A MOIST ATMOSPHERE AND SOME UPPER LEVEL SUPPORT SWINGING THROUGH. LOWS IN THE LOWER TO MID 60S SEEMS REASONABLE GIVEN EXPECTED CLOUD COVER AND DEW POINTS. /08 TUESDAY LOOKING PRETTY UNEVENTFUL DURING MUCH OF THE DAY WITH WAVE EXITING IN THE EAST EARLY IN THE MORNING...LEADING TO PARTLY TO MOSTLY SUNNY SKIES AND SLIGHTLY WARMER TEMPERATURES...IN THE LOWER TO MID 80S...AND MODERATE HUMIDITY WITH DEWPOINTS IN THE MID AND UPPER 60S. WITH A FRONTAL BOUNDARY MEANDERING OVER OUR FAR WEST...MAY SEE A FEW SHOWERS AND THUNDERSTORMS DEVELOP IN OUR NORTHWEST BY LATE AFTERNOON. BETTER CHANCE OF STORMS WILL OCCUR BY TOMORROW EVENING INTO TUESDAY NIGHT AS THETA E ADVECTION AND CONVERGENCE INCREASES ALONG THE FRONT. COULD SEE A FEW SEVERE STORMS IN THE LATE AFTERNOON OR EVENING WITH INCREASING SHEAR AND MID LEVEL LAPSE RATES IN THE VICINITY OF THE FRONT...AND CAPE VALUES AROUND 1500 TO 2000 J/KG OVER THAT AREA. THE BOUNDARY WILL MOVE ONLY VERY SLOWLY EASTWARD LATE TUESDAY NIGHT INTO WEDNESDAY...AND WITH FORCING NOT AS GOOD...THERE WILL BE A LESSER CHANCE OF SHOWERS AND THUNDERSTORMS AS THE SYSTEM TRACKS TO THE EAST. WITH CLOUDS/POSSIBLE SHOWERS AND THE SLIGHTLY COOLER AIRMASS BEHIND THE FRONT...HIGHS ON WEDNESDAY WILL BE IN THE UPPER 70S TO LOWER 80S. THE REMAINDER OF THE WEEK INTO THE EARLY PART OF THE WEEKEND IS LOOKING TO BE DRY AS THE TROUGH OVER THE CENTRAL U.S. AT MIDWEEK PUSHES TO THE EAST...PUTTING OUR AREA INTO A NORTHWESTERLY UPPER LEVEL FLOW. HIGHS FOR THURSDAY AND FRIDAY LOOK TO BE IN THE LOWER 80S WITH LOWS IN THE UPPER 50S TO LOWER 60S. NEXT POSSIBILITY FOR SHOWERS/THUNDERSTORMS WILL BE LATER ON SATURDAY WITH THE NEXT SYSTEM...THOUGH MODELS HAVE USUAL TIMING/PLACEMENT ISSUES THIS FAR OUT. /JM && .AVIATION... SCATTERED SHOWERS AND THUNDERSTORMS...BETTER CHANCES AT KFSD AND KSUX WITH LESSER CHANCES AROUND KHON...WILL CONTINUE THROUGH ABOUT 5Z...BECOMING MUCH MORE ISOLATED THEREAFTER. SKIES SHOULD REMAIN MAINLY VFR BUT SOME PATCHY FOG AND CEILINGS AROUND 1500 FEET POSSIBLE AT KFSD AND KSUX AS THE SYSTEM LIFTS OUT THIS EVENING. FOG SHOULD NOT BE A PROBLEM OVERNIGHT. /08 && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SIOUX FALLS SD 1121 AM CDT MON JUL 05 2010 SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098- IAZ001>003-012>014-020>022-031-032-NEZ013-014-061200- 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- 1121 AM CDT MON JUL 05 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST SOUTH DAKOTA... SOUTHWEST MINNESOTA...NORTHWEST IOWA...AND NORTHEAST NEBRASKA. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS... SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED THROUGH THE DAY...ALTHOUGH MOST ACTIVITY WILL BE SHORT LIVED. A FEW OF THE STORMS MAY CONTAIN BRIEF HEAVY RAINFALL. FLOODING... THE JAMES RIVER WILL REMAIN IN FLOOD FOR THE FORESEEABLE FUTURE. ELSEWHERE...RIVERS CONTINUE TO FALL. THE FIRESTEEL CREEK NEAR MOUNT VERNON WILL BE IN FLOOD THIS WEEK...AND THE BIG SIOUX RIVER NEAR BROOKINGS UNTIL LATE THIS WEEK. THE LITTLE SIOUX RIVER NEAR LINN GROVE AND CHEROKEE WILL ALSO BE IN FLOOD UNTIL EARLY TO MID WEEK. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY THERE IS ANOTHER CHANCE OF THUNDERSTORMS WITH LOCALLY HEAVY RAIN MOVING EASTWARD OVER THE AREA TUESDAY NIGHT INTO WEDNESDAY. SEVERE WEATHER IS NOT EXPECTED AT THE PRESENT TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT. && FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT WWW.WEATHER.GOV/SIOUXFALLS. THIS INCLUDES THE GRAPHICAL HAZARDOUS WEATHER OUTLOOK.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SIOUX FALLS SD 422 PM CDT MON JUL 5 2010 IAZ001-012-SDZ067-052245- LYON-SIOUX-LINCOLN- INCLUDING THE CITIES OF...ROCK RAPIDS...GEORGE...INWOOD... LARCHWOOD...ORANGE CITY...SIOUX CENTER...CANTON...LENNOX...TEA... HARRISBURG 422 PM CDT MON JUL 5 2010 ...SPECIAL WEATHER STATEMENT... FUNNELS HAVE BEEN REPORTED ALL AFTERNOON IN AREAS ACROSS NORTHWEST IOWA AND SOUTHWEST MINNESOTA. AT 415 PM...THE MOST SERIOUS CONCERN AT THIS TIME HOWEVER...IS ONE FUNNEL WAS REPORTED TO BE TOUCHING THE GROUND...5 TO 7 MILES NORTH OF CANTON IN LINCOLN COUNTY SOUTH DAKOTA. THIS INFORMATION WAS RELAYED BY OFF DUTY LAW ENFORCEMENT PERSONNEL. THERE IS AN OUTFLOW BOUNDARY THAT THIS BRIEF TORNADO LIKELY SPUN UP ON. ROTATION IS NOT SEEN ON THE NATIONAL WEATHER SERVICE DOPPLER RADAR...EVEN BELOW ONE THOUSAND FEET VERY CLOSE TO THE SURFACE. THEREFORE IT IS LIKELY DUE TO A LACK OF ROTATIONAL ORGANIZATION...THAT ANY TOUCHDOWN WILL BE VERY BRIEF...TOO BRIEF TO PUT OUT A TORNADO WARNING AT THIS TIME. THIS SITUATION WILL BE MONITORED EXTREMELY CLOSE HOWEVER FOR FUTURE TORNADO WARNINGS. IF YOU SEE FUNNEL CLOUDS OR BRIEF SPIN UP TORNADOES...YOU ARE ENCOURAGED TO SEEK SHELTER...ESPECIALLY IN SIOUX AND LYON COUNTIES IN NORTHWEST IOWA LATE THIS AFTERNOON. MJF
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
436 PM CDT MON JUL 05 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0415 PM FLASH FLOOD SIOUX FALLS 43.54N 96.73W
07/05/2010 MINNEHAHA SD NWS EMPLOYEE
MANY REPORTS OF URBAN FLOODING IN SIOUX FALLS. AREAS SUCH
AS EMPIRE MALL AREA AND KIWANIS AVENUE.
&&
MJFThe Sioux Falls radar (KFSD), 113 km away, was scanning. The volume nearest the first event began at 22:10 UTC.
1 flash flood. Local standard time, as filed.
Heavy rain on saturated ground caused flash flooding of roads, parks, campgrounds, and other low areas in the Okoboji and Spirit Lake areas.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2010Every state in 2010This day in weather historyWarnings in Iowa, July 2010
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: 249064.