In the early morning hours of the 9th, a cluster of elevated thundestorms moved from eastern South Dakota into western Minnesota. One storm dropped large hail near Norcross in Grant County, which was the first severe thunderstorm event of the season.
Every event with a place to put it. Tap one for its entry below.
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.
In the early morning hours of the 9th, a cluster of elevated thundestorms moved from eastern South Dakota into western Minnesota. One storm dropped large hail near Norcross in Grant County, which was the first severe thunderstorm event of the season.
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 May 8, 7:44 PM CST, 5 hours 31 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 844 PM CDT SUN MAY 8 2011 .DISCUSSION... FORECAST CHALLENGE TONIGHT AND MONDAY IS SHOWER AND THUNDERSTORM ACTIVITY AND WINDS. PRECIPITATION IS EXPECTED TO INCREASE IN AREAL EXTENT AND INTENSITY OVERNIGHT AS THE EXIT REGION OF A 40 KNOT 850 MILLIBAR LOW LEVEL JET ESTABLISHES ITSELF ACROSS THE SOUTHERN FA. SHOWALTER INDEX VALUES INDICATE ELEVATED INSTABILITY SHOULD SPREAD NORTHWARD ACROSS THE SOUTHERN HALF OF THE FA AFTER 06Z. THE TIGHT INSTABILITY GRADIENT OVER THE AREA MAY RESULT IN ISOLATED SEVERE STORMS OVERNIGHT IN THE FAR SOUTHWESTERN FORECAST AREA. TEMPERATURE GRIDS FOR THE OVERNIGHT HOURS STILL LOOK ON TRACK. WIND AND WIND GUST GRIDS WERE INCREASED SLIGHTLY OVERNIGHT THROUGH MONDAY NIGHT TO BETTER MATCH NEIGHBORS. NORTHEASTERLY WINDS WILL LIKELY CAUSE WAVE GENERATION IN THE DEVILS LAKE BASIN. THUS...A SPECIAL WEATHER STATEMENT HAS BEEN ISSUED TO HIGHLIGHT WAVE ACTION DUE TO INCREASING EASTERLY WINDS IN THE DEVILS LAKE BASIN MONDAY INTO MONDAY NIGHT. INLAND LAKES WIND AND WAVE MODEL INDICATES THE POTENTIAL OF UP TO 3 FOOT WAVES ON THE WESTERN AND SOUTHERN SHORELINES. && .AVIATION... VFR CEILINGS THIS EVENING SHOULD GIVE WAY TO MVFR CONDITIONS LATER TONIGHT AS MORE ABUNDANT MOISTURE AND WIDESPREAD PRECIPITATION MOVES ACROSS THE FORECAST AREA OVERNIGHT. THE BEST CHANCE FOR TSRA OVERNIGHT SHOULD REMAIN GENERALLY SOUTH OF A KDVL-KFAR-KDTL-KPKD LINE. SCT TSRA ARE EXPECTED TO DEVELOP AGAIN MONDAY AFTERNOON ACROSS MOST OF THE FORECAST AREA. EAST TO NORTHEAST SURFACE WINDS ARE EXPECTED TO INCREASE AGAIN MONDAY WITH GUSTS NEAR 25 KNOTS...ESPECIALLY NEAR KDVL. && .HYDROLOGY... MODERATE TO MINOR FLOODING CONTINUES IN THE BASIN OF THE RED RIVER OF THE NORTH...WITH THE EXCEPTION OF WEST FARGO WHICH IS STILL IN MAJOR CATEGORY. WAHPETON IS THE FIRST POINT ON THE MAINSTEM TO EASE BELOW MINOR FLOOD STAGE. DRY WEATHER THE PAST FEW DAYS HAS ALLOWED RUNOFF TO CONTINUE TO MAKE ITS WAY THROUGH THE RIVER SYSTEM. DEPENDING ON THE EVENTUAL TRACK OF THE DEVELOPING STORM...PRECIPITATION THE NEXT 3 DAYS COULD EXCEED AN INCH OVER THE NORTHERN RED RIVER VALLEY AND DEVILS LAKE BASIN. ALL AREA RIVERS ARE CURRENTLY RESPONDING AS FORECAST. AS THE CURRENT FORECASTS CONTAIN ONLY 24 HOURS OF FORECAST PRECIPITATION...ADDITIONAL RAINFALL WOULD HAVE TO BE FACTORED INTO LATER PREDICTIONS. THE MOST LIKELY SCENARIO IS A SLOWING IN THE RATE OF FALL OR MINOR RISES...ALL DEPENDENT ON WHERE THE HEAVIEST RAINS OCCUR. AREAL FLOOD WARNINGS CONTINUE ALONG THE MAINSTEM RED NORTH OF OSLO TO CANADA...IN CASS COUNTY FROM KINDRED TO HARWOOD...IN PEMBINA COUNTY DOWNSTREAM OF WALHALLA THROUGH NECHE INTO PEMBINA. A FLOOD ADVISORY HAS REPLACED THE AREAL FLOOD WARNING IN THE DEVILS LAKE BASIN AS OVERLAND RUNOFF HAS SUBSIDED. SEE SPECIFIC FLOOD STATEMENTS FOR MORE DETAILS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && BRAMER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND FORKS ND 642 AM CDT SUN MAY 8 2011 MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024- 026>030-038-039-049-052>054-091145- 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- 642 AM CDT SUN MAY 8 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN NORTH DAKOTA...WEST CENTRAL AND NORTHWEST MINNESOTA. .DAY ONE...TODAY AND TONIGHT SCATTERED SHOWERS AND A FEW ISOLATED THUNDERSTORMS WILL MOVE INTO THE SOUTHERN RED RIVER VALLEY THIS MORNING AND SPREAD NORTH AND EASTWARD DURING THE DAY TODAY. THE ACTIVITY WILL CONTINUE THROUGH MUCH OF THE OVERNIGHT HOURS...WITH SOME HEAVY RAIN POSSIBLE IN THE DEVILS LAKE BASIN. WIDESPREAD SPRING SNOW MELT AREAL AND RIVERINE FLOODING CONTINUES ALONG THE RED RIVER AND ITS TRIBUTARIES. REFER TO THE LATEST FLOOD WARNINGS AND STATEMENTS FOR DETAILED INFORMATION ON SPECIFIC LOCATIONS. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE INTO MONDAY. HEAVIEST RAINFALL AMOUNTS SEEM TO BE MOST LIKELY IN THE DEVILS LAKE BASIN TO NORTHERN RED RIVER VALLEY...WHICH COULD AGGRAVATE EXISTING FLOODING. AN UPPER STORM SYSTEM MOVING INTO THE PLAINS WILL BRING A CONTINUED CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH THE MIDDLE PART OF THE WORK WEEK. A WARM FRONT MOVING NORTH ACROSS THE REGION AHEAD OF THE MAIN STORM SYSTEM COULD BE THE FOCUS FOR MORE ORGANIZED THUNDERSTORMS TUESDAY AFTERNOON AND EVENING. THE SITUATION IS STILL UNCERTAIN...BUT AT THIS TIME IT APPEARS THAT THE FIRST SEVERE CONVECTIVE WEATHER OF THE SEASON IS POSSIBLE...WITH HAIL AND DAMAGING WINDS. WIDESPREAD SPRING SNOW MELT AREAL AND RIVERINE FLOODING CONTINUES ALONG THE RED RIVER AND ITS TRIBUTARIES. REFER TO THE LATEST FLOOD WARNINGS AND STATEMENTS FOR DETAILED INFORMATION ON SPECIFIC LOCATIONS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED. JR
SPECIAL WEATHER STATEMENT..CORRECTION NATIONAL WEATHER SERVICE GRAND FORKS ND 835 PM CDT SUN MAY 8 2011 NDZ006-007-014-015-026-054-101215- TOWNER-CAVALIER-BENSON-RAMSEY-NELSON-WESTERN WALSH- INCLUDING THE CITIES OF...CANDO...LANGDON...MADDOCK...LEEDS... DEVILS LAKE...LAKOTA...ADAMS 835 PM CDT SUN MAY 8 2011 ...WAVE ACTION EXPECTED IN THE DEVILS LAKE BASIN INTO MONDAY NIGHT... A SLOW MOVING LOW PRESSURE AREA IN THE CENTRAL PLAINS WILL CONTINUE TO MOVE NORTHWARD INTO THE DAKOTAS MONDAY AND MONDAY NIGHT. AS A RESULT...EASTERLY WINDS WILL GRADUALLY SHIFT NORTHEAST BY MONDAY AFTERNOON AND INCREASE TO BETWEEN 15 TO 25 MPH WITH GUSTS APPROACHING 30 MPH. THE WINDS ARE EXPECTED TO PERSIST THROUGH MONDAY NIGHT. WINDS AT THESE SPEEDS WILL LIKELY GENERATE WAVE ACTION OF 1 TO 3 FEET ON THE WESTERN AND SOUTHERN SHORES OF LAKES AND FLOODED AREAS WITHIN THE DEVILS LAKE BASIN. THIS WILL IMPACT HIGHWAYS 2...20..57 AND 281 ALONG WITH NUMEROUS COUNTY ROADS IN THE AREA. IN ADDITION...WAVE ACTION MAY AFFECT THE COMMUNITIES OF MINNEWAUKAN...CHURCHS FERRY...FORT TOTTEN...SAINT MICHAEL...AND TOKIO MONDAY AFTERNOON THROUGH MONDAY NIGHT. MOTORISTS IN THE REGION SHOULD BE ON THE LOOKOUT FOR WAVES AND FLOATING DEBRIS WASHING UP ON ROADWAYS. IN ADDITION...AREAS PRONE TO ROADBED EROSION MAY SEE DEGRADATION OF RIPRAP ON SHOULDERS. BRAMER
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 943 PM CDT SUN MAY 8 2011 NDZ038-090345- BARNES ND- 943 PM CDT SUN MAY 8 2011 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN BARNES COUNTY UNTIL 1045 PM CDT... AT 941 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING THUNDERSTORMS ALONG A LINE EXTENDING FROM 17 MILES EAST OF JAMESTOWN TO 26 MILES WEST OF LISBON...MOVING TO THE EAST AT 25 MPH. HAIL UP TO THE SIZE OF PENNIES IS EXPECTED WITH THE STORMS. THE STORMS WILL BE NEAR... HASTINGS AROUND 1000 PM CDT. KATHRYN AROUND 1010 PM CDT. VALLEY CITY AROUND 1020 PM CDT. NOME AROUND 1025 PM CDT. FOR MOTORISTS ON INTERSTATE 94...THE STORMS WILL BE BETWEEN NORTH DAKOTA MILE MARKER 276 AND NORTH DAKOTA MILE MARKER 305... BE PREPARED TO TAKE SHELTER IF THE STORMS INTENSIFY AND BECOME SEVERE...OR A WARNING IS ISSUED BY THE NATIONAL WEATHER SERVICE. DK
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 1201 AM CDT MON MAY 9 2011 NDZ038-090600- BARNES ND- 1201 AM CDT MON MAY 9 2011 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN BARNES COUNTY UNTIL 100 AM CDT... AT MIDNIGHT CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A THUNDERSTORM 21 MILES SOUTHEAST OF JAMESTOWN...MOVING TO THE NORTHEAST AT 25 MPH. HAIL UP TO THE SIZE OF NICKELS IS EXPECTED WITH THE STORM. THE STORM WILL BE NEAR... LITCHVILLE AROUND 1210 AM CDT. HASTINGS AROUND 1225 AM CDT. KATHRYN AROUND 1235 AM CDT. VALLEY CITY AND NOME AROUND 1250 AM CDT. FOR MOTORISTS ON INTERSTATE 94...THE STORM WILL BE BETWEEN...MILE MARKER 287 AROUND 1240 AM CDT...AND MILE MARKER 305 AROUND 100 AM CDT... BE PREPARED TO TAKE SHELTER IF THE STORMS INTENSIFY AND BECOME SEVERE...OR A WARNING IS ISSUED BY THE NATIONAL WEATHER SERVICE. DK
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 115 AM CDT MON MAY 9 2011 MNZ029-NDZ049-052-053-090715- RANSOM ND-RICHLAND ND-SARGENT ND-WILKIN MN- 115 AM CDT MON MAY 9 2011 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN SARGENT...NORTHERN RICHLAND...SOUTHEASTERN RANSOM AND WESTERN WILKIN COUNTIES UNTIL 215 AM CDT... AT 114 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A THUNDERSTORM 9 MILES SOUTHWEST OF WYNDMERE...OR 33 MILES WEST OF WAHPETON...MOVING TO THE NORTHEAST AT 20 MPH. HAIL UP TO THE SIZE OF PENNIES IS EXPECTED WITH THE STORM...ALONG WITH HEAVY RAIN. THE STORM WILL BE NEAR... DE LAMERE AROUND 120 AM CDT. WYNDMERE AND MCLEOD AROUND 135 AM CDT. BARNEY AROUND 150 AM CDT. WALCOTT...GALCHUTT AND COLFAX AROUND 215 AM CDT. BE PREPARED TO TAKE SHELTER IF THE STORMS INTENSIFY AND BECOME SEVERE...OR A WARNING IS ISSUED BY THE NATIONAL WEATHER SERVICE. TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED ROADWAY. DK
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 142 AM CDT MON MAY 9 2011 MNZ003-027-029-NDZ039-053-090745- CASS ND-CLAY MN-RICHLAND ND-WEST BECKER MN-WILKIN MN- 142 AM CDT MON MAY 9 2011 ...SIGNIFICANT WEATHER ADVISORY FOR EXTREME SOUTHWESTERN BECKER AND SOUTHERN CLAY COUNTIES IN NORTHWEST MINNESOTA...AND EXTREME NORTHWESTERN WILKIN COUNTY IN WEST CENTRAL MINNESOTA...AND SOUTHEASTERN CASS AND EXTREME NORTHERN RICHLAND COUNTIES IN SOUTHEAST NORTH DAKOTA UNTIL 245 AM CDT... AT 137 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A THUNDERSTORM 9 MILES SOUTHEAST OF HORACE...OR 13 MILES SOUTH OF FARGO...MOVING TO THE NORTHEAST AT 20 MPH. HAIL UP TO ONE-HALF INCH IN DIAMETER IS EXPECTED WITH THE STORM... ALONG WITH HEAVY RAIN. THE STORM WILL BE NEAR... SABIN AROUND 200 AM CDT. BAKER AROUND 205 AM CDT. GLYNDON AND DOWNER AROUND 220 AM CDT. MUSKODA AROUND 240 AM CDT. FOR MOTORISTS ON INTERSTATE 94...THE STORM WILL BE BETWEEN...MILE MARKER 5 AROUND 205 AM CDT...AND MILE MARKER 21 AROUND 215 AM CDT... BE PREPARED TO TAKE SHELTER IF THE STORMS INTENSIFY AND BECOME SEVERE...OR A WARNING IS ISSUED BY THE NATIONAL WEATHER SERVICE. TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED ROADWAY. DK
The Fargo/Grand Forks radar (KMVX), 100 km away, was scanning. The volume nearest the first event began at 07:14 UTC.
1 flash flood, 1 hail. Local standard time, as filed.
Two to three inches of heavy rain produced street flooding in the community of Comstock, in nearby farm fields, and across several sections of road in western Holy Cross township. Flooding conditions along adjacent portions of the Red River were also increased.
After the storm passed there were drifts of hail several inches deep in one yard.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2011Every state in 2011This day in weather historyWarnings in Minnesota, May 2011
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: 317473, 290105.