Flash Flood in South Dakota, August 21, 2002

Name: Flash Flood in South Dakota, August 21, 2002
Start: 2002-08-21T05:20
End: 2002-08-21T08:00
Location: South Dakota

August 21, 2002 · NWS FSD · 1 event in 1 county or zone

1 flash flood, as filed by the National Weather Service.

Where it happened

Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. 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: 0
Injuries: 0
Property damage: $100,000
Crop damage: None recorded
Events: 1

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 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 Sioux Falls, SD wrote its last area forecast discussion before the first event at Aug 21, 2:30 AM CST, 2 hours 50 minutes earlier.

Area forecast discussion, Aug 21, 2:30 AM CST, 2 hours 50 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
330 AM CDT WED AUG 21 2002

AS OF 08Z LINE OF TSTMS WERE SLOWLY PULLG NE OVR SE SD AND SW MN.
HVY RAIN HAS BEEN THE PRBLM THE LAST FEW HOURS BUT NO REPORTS OF ANY
FLOODG PROBLEMS. SCTD SHWRS IN WRN AREAS NW OF TSTMS LINE WHILE IN
SE AREAS OVR NW IA IT STILL IS DRY. WILL PUT A LOW CHC OF SOMETHING
MAKING IT INTO NW IA THIS MRNG. PCP SHLD WEND FM W TO E THIS MRNG
WITH IT DRY THIS AFTN AND THEN REFORM AGN BY EVE WITH BNDRY FM SE SD
INTO SW MN AND HEATG OF DAY. TSTMS WILL CONT ALNG BNDRY INTO TNGT AS
S/WV MOVES THRU FM W WITH BEST CHC OVR EXTRM SE SD INTO NW IA WHERE
MOST SGNFNT RAIN SHLD OCCUR. KEEP CHC OF SHWRS AND TSTMS GOING OVR
SRN PARTS OF CWA OF N OF BNDRY WHERE THERE IS PLNTY OF MSTR AND S/WV
MOVG THRU. CRNT FCST HAS IT DRYING OUT FOR FRI BUT MODELS TRYG TO
SHOW VORT MAX MOVG E OVR SRN PARTS OF CWA THAT COULD BRING A CHC OF
TSTMS THRU SRN ZNS. WILL ADD A CHC THERE FOR FRI. OTRW LOOKS TO BE
DRY AND COOL INTO FIRST OF NEXT WEEK.

.FSD...NONE
45

In the hours before

Local storm report, Aug 20, 11:34 PM CST, 5 hours 46 minutes before

PRELIMINARY LOCAL STORM REPORT...event summary
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1234 AM CDT WED AUG 21 2002

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0732 PM    8 N PLANKINTON            SD   .75 INCH HAIL
08/20/02   AURORA                         REPORTED BY STORM
                                          SPOTTER.

0735 PM    5 ESE LETCHER             SD   1 INCH HAIL
08/20/02   SANBORN                        REPORTED BY STORM
                                          SPOTTER.

0757 PM    7 NNW MT VERNON           SD   .75 INCH HAIL
08/20/02   DAVISON                        REPORTED BY STORM
                                          SPOTTER.

0807 PM    8 NNE MT VERNON           SD   .88 INCH HAIL
08/20/02   DAVISON                        REPORTED BY STORM
                                          SPOTTER.

0808 PM    1 N LOOMIS                SD   .75 INCH HAIL
08/20/02   DAVISON                        REPORTED BY STORM
                                          SPOTTER.

0810 PM    LOOMIS                    SD   .88 INCH HAIL
08/20/02   DAVISON                        REPORTED BY EMERGENCY
                                          MANAGEMENT.

0810 PM    5 W MITCHELL              SD   .88 INCH HAIL
08/20/02   DAVISON                        REPORTED BY EMERGENCY
                                          MANAGEMENT.

0820 PM    5 SW MITCHELL             SD   1.75 INCH HAIL
08/20/02   DAVISON                        REPORTED BY STORM
                                          SPOTTER.

0847 PM    2 S MITCHELL              SD   .88 INCH HAIL
08/20/02   DAVISON                        REPORTED BY STORM
                                          SPOTTER.

0850 PM    1 N EPIPHANY              SD   65 MPH TSTM GUST
08/20/02   MINER                          REPORTED BY STORM
                                          SPOTTER.

0855 PM    ALEXANDRIA                SD   60 MPH TSTM GUST
08/20/02   HANSON                         REPORTED BY STORM
                                          SPOTTER.

0905 PM    9 S WINFRED               SD   60 MPH TSTM GUST
08/20/02   LAKE                           REPORTED BY STORM
                                          SPOTTER.

0910 PM    4 NW FARMER               SD   .88 INCH HAIL
08/20/02   HANSON                         REPORTED BY STORM
                                          SPOTTER.

0910 PM    FARMER                    SD   60 MPH TSTM GUST
08/20/02   HANSON                         REPORTED BY STORM
                                          SPOTTER.

0915 PM    1 NE SPENCER              SD   65 MPH TSTM GUST
08/20/02   MCCOOK                         REPORTED BY STORM
                                          SPOTTER.

0930 PM    EMERY                     SD   60 MPH TSTM GUST
08/20/02   HANSON                         REPORTED BY STORM
                                          SPOTTER.

0930 PM    EMERY                     SD   60 MPH TSTM GUST
08/20/02   HANSON                         SMALL TREE LIMBS DOWN
                                          ALSO.  REPORTED BY
                                          STORM SPOTTER.

0935 PM    STICKNEY                  SD   .75 INCH HAIL
08/20/02   AURORA                         REPORTED BY STORM
                                          SPOTTER.

0937 PM    3 S EMERY                 SD   TORNADO
08/20/02   HANSON                         REPORTED BY STORM CHASER

0947 PM    CORSICA                   SD   1 INCH HAIL
08/20/02   DOUGLAS                        REPORTED BY LAW
                                          ENFORCEMENT OFFICIAL.

1000 PM    8 N MITCHELL              SD   FLOOD
08/20/02   DAVISON                        WATER OVER COUNTY ROAD
                                          AND WATER IN BASEMENT.
                                          REPORTED BY STORM
                                          SPOTTER.

1023 PM    4 S SALEM                 SD   .88 INCH HAIL
08/20/02   MCCOOK                         REPORTED BY STORM
                                          SPOTTER.

The radar

The Sioux Falls radar (KFSD), 11 km away, was scanning. The volume nearest the first event began at 11:36 UTC.

Open the radar archive at this moment

Event by event

1 flash flood. Local standard time, as filed.

Flash Flood, Minnehaha

When: August 21, 5:20 AM CST to 8:00 AM CST
Where: Minnehaha County, Sioux Falls
Property damage: $100,000
Reported by: NWS EMPLOYEE(OFF DUTY)
Coordinates: 43.674, -96.791 (the zone’s center; the record gives no point)

Heavy rainfall up to six and a half inches caused widespread street flooding. There was around a foot of standing water in many places, and several motorists were stranded trying to drive through flooded areas. Many basements were also flooded. At least one basement wall collapsed, and another suffered severe cracking.

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.

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

The same day elsewhere

Every storm in South Dakota in 2002 Every state in 2002 This day in weather history Warnings in South Dakota, August 2002

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: 5317616.