Isolated strong thunderstorms formed across portions of Richland and Cass counties during the early morning hours of the 29th. These storms produced very large hail.
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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 FGF wrote it up.
Isolated strong thunderstorms formed across portions of Richland and Cass counties during the early morning hours of the 29th. These storms produced very large hail. Several hours later a line of thunderstorms approached the New Rockford, North Dakota, area, and began to bow, which is indicative of strong winds. This bowing signature on radar continued as the line of thunderstorms tracked eastward along U. S. Highway 2 toward the Grand Forks (ND) and Oslo (MN) areas, where they gradually weakened.
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 28, 10:22 PM CST, 2 hours 53 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 1122 PM CDT WED AUG 28 2013 .UPDATE... ISSUED AT 1120 PM CDT WED AUG 28 2013 NO MAJOR CHANGES PLANNED TO THIS UPDATE. A BAND OF CONVECTION WILL MOVE INTO WESTERN/CENTRAL ND OVERNIGHT AHEAD OF A STRONGER SHORTWAVE. ADDITIONAL SHOWERS/STORMS MAY DEVELOP OVER EASTERN ND LATER TONIGHT WITH INCREASING MID LEVEL WAA AND INSTABILITY. THIS IS ALL HANDLED WELL IN THE CURRENT GRIDS. THERE COULD BE SOME VERY PATCHY FOG BEFORE CLOUDS INCREASE...BUT WITH NO EVIDENCE OF FOG YET AND THE HRRR NOT INDICATING ANY...FOR NOW WILL LEAVE OUT...BUT SOMETHING TO MONITOR. THERE COULD BE SEVERE STORMS LATER TONIGHT AND A BETTER CHANCE ON THU...WITH AMPLE INSTABILITY/SHEAR. PWATS ALSO RISE OVER 2 INCHES IN SOME AREAS...SO LOCALLY HEAVY RAIN WILL ALSO BE A THREAT. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 323 PM CDT WED AUG 28 2013 WEAK SURFACE BOUNDARY HAS DROPPED OUT OF MANITOBA AND EXTENDS FROM FLAG ISLAND TO JUST SOUTH OF ROSEAU TO ST THOMAS TO CANDO. THIS BOUNDARY IS PROGGED TO DROP JUST A BIT SOUTH AND WITH DEW PTS NR 70 ALONG BOUNDARY AND HEATING OF TEMPS INTO THE LOWER 90S ALONG BOUNDARY ALL CAUSING A FEW STORMS TO FIRE. WILL NEED TO INCLUDE ISOLD POP FOR THIS THRU SUNSET. OTHERWISE MAIN ACTION LATE TONIGHT. WATER VAPOR SHOWS NEXT SHORT WAVE MOVING INTO SOUTHWEST MONTANA AT 19Z. THIS SHORT WAVE WILL MOVE EAST ON TOP OF THE 500 MB RIDGE AND INTO ERN ND TOWARD 12Z AND THEN INTO MINNESOTA THURSDAY THROUGH 18Z. ALL MODELS INDICATE A 30-35 KT LOW LEVEL JET ALONG 850 MB BOUNDARY WHICH WILL LIE IN THE CENTRAL PART OF THE STATE LIKELY JUST NORTH OF I-94. SOUTHEASTERLY UPSLOPE FLOW INTO EASTERN MONTANA AIDING IN STORM DEVELOPMENT THERE AND EXPECT AS SHORT WAVE MOVES INTO CNTRL MONTANA STORM TO GROW IN COVERAGE AND SEEMS AS IF AN MCS IS LIKELY TO FORM AND MOVE EAST INTO WRN ND LATER THIS EVE AND THEN CNTRL ND OVERNIGHT REACHING THE RED RIVER VALLEY LIKELY AFTER 08Z. TRIED TO TIME POPS A BIT MORE TOWARD THAT IDEA...WITH LIKELY POPS 09Z-12Z IN MUCH OF ERN ND. SEVERE WX BY THEN QUESTIONABLE....BUT WITH PWATS OF 2.10 INCHES ALONG 850 MB BOUNDARY HEAVY RAIN SEEMS REASONABLE. COULD BE LOCALIZED FLASH FLOODING ISSUES BUT WHERE AND WHEN CANNOT SAY AND CONDITIONS PRIOR TO RAIN HAVE BEEN VERY VERY DRY. SYSTEM WILL MOVE EAST WITH PRECIP ENDING IN THE MORNING IN ERN ND AND IN THE AFTN IN NW MN. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 323 PM CDT WED AUG 28 2013 DRY THURSDAY NIGHT AND FRIDAY WITH HIGH PRESSURE MOVING. A TAD COOLER BUT NOT MUCH. FOR SATURDAY THROUGH WEDNESDAY...LONG WAVE PATTERN IS ZONAL AND SPLIT ACROSS NORTH AMERICA AT THE BEGINNING OF THE PERIOD AND AMPLIFIES BY THE END OF THE PERIOD. LONG WAVE UPPER RIDGE REMAINS FROM THE DESERT SOUTHWEST INTO MT. THE ECMWF AND GFS WERE IN AGREEMENT AT 84 HOURS. THE ECMWF IS A FASTER SOLUTION THAN THE GFS BY THE END OF THE PERIOD. BOTH GFS AND ECMWF HAVE SHIFTED WEST IN THE LAST MODEL RUN. WILL BLEND THE ECMWF AND GFS. WILL KEEP YESTERDAYS PRECIP FOR SAT NIGHT. BUMPED UP POPS FOR SUN. TOOK OUT PRECIP FOR TUE. TEMPERATURES WERE LOWERED A DEGREE OR TWO FOR SUN AND MON AND RAISED ONE OR TWO DEGREES FOR TUE AND WED COMPARED TO YESTERDAYS RUN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1120 PM CDT WED AUG 28 2013 THE CHANCE FOR SHOWERS AND STORMS WILL INCREASE FROM WEST TO EAST BY LATE TONIGHT INTO THU. EXPECT MAINLY VFR CONDITIONS...ALTHOUGH MVFR AND EVEN IFR CONDITIONS ARE POSSIBLE NEAR STRONGER STORMS CONTAINING VERY HEAVY RAIN AND STRONGER WINDS. THE BEST CHANCE FOR PROLONGED RAIN TOMORROW SHOULD OCCUR ACROSS THE NORTH. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && UPDATE...DK SHORT TERM...RIDDLE LONG TERM...HOPPES/RIDDLE AVIATION...DK
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND FORKS ND 634 AM CDT WED AUG 28 2013 MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024- 026>030-038-039-049-052>054-291145- WEST POLK-NORMAN-CLAY-KITTSON-ROSEAU-LAKE OF THE WOODS- WEST MARSHALL-EAST MARSHALL-NORTH BELTRAMI-PENNINGTON-RED LAKE- EAST POLK-NORTH CLEARWATER-SOUTH BELTRAMI-MAHNOMEN- SOUTH CLEARWATER-HUBBARD-WEST BECKER-EAST BECKER-WILKIN- WEST OTTER TAIL-EAST OTTER TAIL-WADENA-GRANT-TOWNER-CAVALIER- PEMBINA-BENSON-RAMSEY-EASTERN WALSH-EDDY-NELSON-GRAND FORKS- GRIGGS-STEELE-TRAILL-BARNES-CASS-RANSOM-SARGENT-RICHLAND- WESTERN WALSH- 634 AM CDT WED AUG 28 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN NORTH DAKOTA...WEST CENTRAL AND NORTHWEST MINNESOTA. .DAY ONE...TODAY AND TONIGHT AN AREA OF THUNDERSTORMS IS EXPECTED TO DEVELOP TONIGHT. A FEW STRONGER STORMS WILL BE POSSIBLE. HEAVY RAINFALL IS POSSIBLE AS THUNDERSTORMS MAY TRAIN OVER A LOCATION FOR AN EXTENDED PERIOD OF TIME. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY REDEVELOPMENT MAY OCCUR AND THUNDERSTORMS WILL BE POSSIBLE LATER THURSDAY AFTERNOON INTO THE EVENING HOURS ALONG AND EAST OF THE RED RIVER VALLEY. STRONG TO SEVERE STORMS MAY DEVELOP MOST LIKELY AREA WILL BE WCNTRL MN. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS POSSIBLE THURSDAY.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 130 AM CDT THU AUG 29 2013 NDZ049-052-053-290730- RANSOM ND-RICHLAND ND-SARGENT ND- 130 AM CDT THU AUG 29 2013 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN RICHLAND... NORTHEASTERN SARGENT AND SOUTHEASTERN RANSOM COUNTIES UNTIL 230 AM CDT... AT 125 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A THUNDERSTORM 6 MILES EAST OF MILNOR...OR 35 MILES WEST OF WAHPETON... MOVING TO THE NORTHEAST AT 15 MPH. HAIL UP TO THE SIZE OF NICKELS IS EXPECTED WITH THE STORM. THE STORM WILL BE NEAR... DE LAMERE AROUND 135 AM CDT. WYNDMERE AROUND 155 AM CDT. MCLEOD AROUND 205 AM CDT. BE PREPARED TO TAKE SHELTER IF THE STORMS INTENSIFY AND BECOME SEVERE...OR A WARNING IS ISSUED BY THE NATIONAL WEATHER SERVICE. LAT...LON 4660 9719 4644 9688 4614 9728 4626 9745 TIME...MOT...LOC 0630Z 216DEG 12KT 4625 9733 TG
The Fargo/Grand Forks radar (KMVX), 115 km away, was scanning. The volume nearest the first event began at 07:16 UTC.
8 thunderstorm wind, 4 hail. Local standard time, as filed.
Hail from nickel to half dollar size occurred across the northwest corner of Colfax West Township.
Hail up to tennis ball size fell in and around Walcott.
Dime to quarter size hail fell north of Casselton.
The strong winds caused a car to shake violently.
Numerous large tree branches were broken in and near Doyon. The grandstands were flipped and a travel trailer tumbled at the Devils Lake Speedway.
Several four to eight inch diameter tree branches were broken down around Lakota.
Several four to eight inch diameter tree branches were blown down in Michigan.
Very strong winds and rain were reported with a few large tree branches torn down around town.
A few large tree branches were blown down in a farm shelterbelt.
Large tree branches were blown down in a shelterbelt.
Several large cottonwood trees were snapped in a shelterbelt.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in North Dakota in 2013Every state in 2013This day in weather historyWarnings in North Dakota, August 2013
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: 466952, 466953, 466954, 466956, 466963, 466957, 466958, 466959, 466964, 466960, 466961, 466962.