Flash Flood and Hail in Minnesota, August 31, 2002

Name: Flash Flood and Hail in Minnesota, August 31, 2002
Start: 2002-08-31T01:35
End: 2002-08-31T23:55
Location: Minnesota

August 31, 2002 · NWS FGF · 12 events in 8 counties and zones

6 thunderstorm wind, 5 hail, 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: $71,000
Crop damage: None recorded
Events: 12

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 Grand Forks, ND wrote its last area forecast discussion before the first event at Aug 31, 1:30 AM CST, 5 minutes earlier.

Area forecast discussion, Aug 31, 1:30 AM CST, 5 minutes before

FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
230 AM CDT SAT AUG 31 2002

MAIN CHALLENGE FOR THIS FORECAST REMAINS PCPN. FIRST ROUND OCCURRING
ATTM AND NEXT SHOT ON TRACK FOR TONIGHT/EARLY SUN. MODELS IN DECENT
AGREEMENT WITH QPF PATTERNS FOR NEXT EVENT AND WILL FOLLOW A MIX FOR
GRIDS.

MAIN SFC TROUGH STILL LOCATED OVER WESTERN NORTH DAKOTA WITH STRONG
SFC PRESSURE GRADIENT OVER RED RIVER VALLEY/NORTHWEST MN PORTION OF
FA. STRONG WINDS MIXING DOWN TO THE SFC WITH KFAR GUSTING TO 30KTS.
KMVX 88D STILL SHOWS 30-40KTS IN THE LOWER GATES FEEDING AMPLE
MOISTURE NORTHWARD INTO CONVECTIVE COMPLEX NOW MOVING INTO NORTHWEST
MN. NWS IN GRAND FORKS ALREADY HAS RECEIVED NEARLY 1.50 INCHES OF
RAIN SO FAR WITH HEAVIER RAIN BAND JUST SOUTH OF THE CITY. HAVE
RECEIVED REPORTS OF STREET FLOODING IN GF. MAIN QUESTION IS HOW TO
HANDLE INHERITED FLOOD WATCH HEADLINE FOR TODAY. HEALTHY LOW LEVEL
JET AXIS SHIFTS INTO NORTHWEST MN BY 12Z SAT WITH MAIN UPPER WAVE
SHIFTING INTO SOUTHERN MANITOBA. WITH SOME CONVECTION YET FIRING IN
FAR SOUTHWEST FA...BELIEVE WE WILL STILL SEE SOME TRAINING ALONG THE
VALLEY AND INTO MN COUNTIES YET THRU THE MORNING. SO WILL REFINE THE
FLOOD WATCH ACCORDINGLY.

NEXT CONCERN IS THE NEXT WAVE DROPPING THRU TONIGHT INTO EARLY SUN.
ALL MODELS SHOWING FAIRLY DECENT QPF ACROSS MAINLY SOUTHERN HALF OF
FA. IN THE WAKE OF THIS MORNINGS DEPARTING CONVECTION...THERE
SHOULD BE SOME CLEARING/HEATING DURING THE DAY. CONVECTIVE TEMPS
INITIALLY QUITE HIGH (90S)...SO BELIEVE MAIN THREAT WILL BE LATE.
850 MB JET GETS CRANKING AGAIN BY 06Z SUN WITH COUPLED 250 MB JET AS
WELL. SPC HAS AREA IN SLIGHT RISK AGAIN AND THEIR SWODY1 DISCUSSION
ALSO MENTIONS BEST CHANCE BEING LATE. SEE POTENTIAL FOR ANOTHER
ROUND OF HEAVY RAIN WITH THIS WAVE...WITH BEST CHANCE SHIFTING
ACROSS SOUTHERN FA. HOWEVER WILL AVOID CONFUSION AT THIS TIME AND
STICK WITH ONE HEADLINE (LET NEXT SHIFT ISSUE A FLOOD WATCH IF
CONDITIONS STILL LOOK FAVORABLE). MAY REMOVE CHANCE OF PCPN ACROSS
SOUTHERN FA SUN NIGHT/MON AS NEW MODEL RUNS LOOKING LESS AGRESSIVE
WITH THIS NEXT EVENT. NO CHANGES TO EXTENDED.

.FGF...FLOOD WATCH ALONG NORTHERN RED RIVER VALLEY AND NORTHWEST
MN ZONES FOR THIS MORNING.

GODON

In the hours before

Local storm report, Aug 30, 9:57 PM CST, 3 hours 38 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND FORKS, ND
1057 PM CDT FRI AUG 30 2002

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

1050 PM    FOREST RIVER              ND   .75 INCH HAIL
08/30/02   WALSH                          REPORTED BY LAW
                                          ENFORCEMENT.

DPORTER

Local storm report, Aug 30, 11:47 PM CST, 1 hour 48 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND FORKS, ND
1247 AM CDT SAT AUG 31 2002

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

1245 AM    REYNOLDS                  ND   .75 INCH HAIL
08/31/02   TRAILL                         REPORTED BY FIRE
                                          DEPARTMENT.

DPORTER

The radar

The Fargo/Grand Forks radar (KMVX), 42 km away, was scanning. The volume nearest the first event began at 07:34 UTC.

Open the radar archive at this moment

Event by event

6 thunderstorm wind, 5 hail, 1 flash flood. Local standard time, as filed.

Hail, Norman

When: August 31, 1:35 AM CST to 1:40 AM CST
Where: Norman County, Halstad
Measured: 0.75 in hail
Reported by: GENERAL PUBLIC
Coordinates: 47.350, -96.833

Hail, Norman

When: August 31, 2:35 AM CST
Where: Norman County, 1 mi N of Borup
Measured: 0.88 in hail
Reported by: GENERAL PUBLIC
Coordinates: 47.200, -96.517

Flash Flood, Polk

When: August 31, 5:00 AM CST to 9:00 AM CST
Where: Polk County, 1 mi W of Crookston
Reported by: GENERAL PUBLIC
Coordinates: 47.774, -96.402 (the zone’s center; the record gives no point)

Water flowed over county roads.

Hail, Beltrami

When: August 31, 6:45 AM CST
Where: Beltrami County, 8 mi N of Bemidji
Measured: 0.75 in hail
Reported by: GENERAL PUBLIC
Coordinates: 47.600, -94.900

Hail, Kittson

When: August 31, 8:05 PM CST
Where: Kittson County, 3 mi W of Humboldt
Measured: 0.75 in hail
Reported by: GENERAL PUBLIC
Coordinates: 48.933, -97.150

Hail, Clay

When: August 31, 10:53 PM CST
Where: Clay County, Moorhead
Measured: 1 in hail
Reported by: GENERAL PUBLIC
Coordinates: 46.883, -96.750

Thunderstorm Wind, Polk

When: August 31, 11:10 PM CST
Where: Polk County, Fisher
Measured: 62 kt (71 mph)
Reported by: GENERAL PUBLIC
Coordinates: 47.800, -96.817

A 71 mph wind gust was measured at a MN DOT RWIS site near Fisher.

Thunderstorm Wind, Polk

When: August 31, 11:20 PM CST
Where: Polk County, Fisher
Measured: 55 kt (63 mph)
Reported by: GENERAL PUBLIC
Coordinates: 47.800, -96.817

A 63 mph wind gust was measured at the MN DOT RWIS site near Fisher.

Thunderstorm Wind, Marshall

When: August 31, 11:40 PM CST to 11:45 PM CST
Where: Marshall County, 5 mi NW of Gatzke
Property damage: $1,000
Reported by: GENERAL PUBLIC
Coordinates: 48.483, -95.867

Many large trees were snapped off.

Thunderstorm Wind, Pennington

When: August 31, 11:45 PM CST
Where: Pennington County, 12 mi W of Thief River Falls
Property damage: $20,000
Reported by: GENERAL PUBLIC
Coordinates: 48.133, -96.450

Large cottonwood trees were uprooted and a grain bin was demolished.

Thunderstorm Wind, Roseau

When: August 31, 11:50 PM CST
Where: Roseau County, Roseau
Property damage: $50,000
Reported by: GENERAL PUBLIC
Coordinates: 48.850, -95.750

Two FEMA trailers and one semi truck were blown over. 1000 feet of electrical wiring needed replacement in the downtown area.

Thunderstorm Wind, Pennington

When: August 31, 11:55 PM CST
Where: Pennington County, Thief River Falls
Measured: 61 kt (70 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 48.133, -96.183

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
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.

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

The same day elsewhere

Every storm in Minnesota in 2002 Every state in 2002 This day in weather history Warnings in Minnesota, 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: 5317995, 5317994, 5317992, 5317993, 5317996, 5317997, 5317998, 5317999, 5318003, 5318000, 5318002, 5318001.