Persistent thunderstorms north of a warm front produced heavy rains over portions of Otter Tail County.
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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.
Persistent thunderstorms north of a warm front produced heavy rains over portions of Otter Tail County.
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 1, 8:30 PM CST, 1 hour 30 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GRAND FORKS ND 930 PM CDT SUN AUG 1 2010 .UPDATE... FCST CHALLENGE OVERNIGHT WILL BE POPS...TEMPS AND RAINFALL AMOUNTS. LATEST RADAR TRENDS HAVE BEEN SHOWING A PERSISTENT CELL OVER TOWNER/CAVALIER COUNTY THAT DID PRODUCE WIND DAMAGE EARLIER NEAR ROCK LAKE AND MUNICH ND WITH SEVERAL LARGE TREES DOWN. OTHERWISE CONTINUING CONVECTION OVER THE FAR ERN COUNTIES IN WCNTRL MN HAS RESULTED IN SOME FLOODING ACROSS SRN BELTRAMI COUNTY. EXPECT ADDITIONAL RAINFALL TO CONTINUE AS 8H WATER TRANSPORT FEEDS MOISTURE INTO THIS REGION FOR THE NEXT SEVERAL HOURS. SFC ANALYSIS INDICATED AN AREA OF LOW PRESSURE ALONG THE ND/SD BORDER SWWD INTO CNTRL SD WITH A WMFNT EXTENDING INTO WCNTRL MN. EXPECT THIS FEATURE TO SLOWLY PROPAGATE EWD OVER NIGHT BRINGING AN END TO THE PRECIP OVER THE ERN/SRN ZONES. CURRENT FCST OVERALL HAS A GOOD HANDLE ON TONIGHTS EVENT. THE ONLY CHANGE WILL BE TO CUT BACK THE POPS IN THE FAR SOUTHERN ZONES SOMEWHAT. WILL ALLOW WATCH 558 TO EXPIRE AT 03Z. && .AVIATION... EXPECT PRIMARILY VFR CONDITIONS OVERNIGHT WITH THE EXCEPTION OF SOME POSSIBLE FOG AT KDVL...KBJI...AND KTVF TOWARD DAYBREAK. WINDS WILL TURN NWLY MON MORNING. && .PREV DISCUSSION... /ISSUED 240 PM CDT SUN AUG 1 2010/ DISCUSSION... FORECAST CHALLENGE CONCERNS T POTENTIAL AND TEMPERATURES. MODELS IN REASONABLE AGREEMENT THROUGH MOST OF SHORT TERM. SOME DIFFERENCES IN STRENGTH OF MID WEEK WAVE WITH THE GFS LOOKING THE STRONGEST AND WILL DISCARD FOR NOW. ONGOING CONVECTION ASSOCIATED WITH A COUPLE OF BOUNDARIES AFFECTING THE FA THIS AFTERNOON. MOST ACTIVE CONVECTION ASSOCIATED WITH WARM FRONT EXTENDING FROM SURFACE LOW OVER N CENTRAL SD EASTWARD ALONG DAKOTAS BORDER THEN INTO SW MN. NOSE OF 850MB LOW LEVEL JET AND WARM ADVECTION MAXIMA VCNTY OF FRONT ALSO AIDING CONVECTION. WEAKER CONVECTION RIDING ALONG INTERNATIONAL BORDER AREA NORTH OF E-W BOUNDARY FROM SFC LOW NEAR ISN EASTWARD ROUGHLY ALONG HIGHWAY 2. STRONGEST DESTABILIZATION CURRENTLY VCNTY WARM FRONT ALONG DAKOTA BORDER AREA SOUTHWARD. NEAR NORTHERN BOUNDARY CAPE AND INSTABILITY MINIMAL ATTM. MOST LIKELY AREA FOR STRONG/SVR STORMS BASED ON CURRENT TRENDS AND ABILITY TO REACH CONVECTIVE TEMPERATURES LOOKS TO BE ACROSS SOUTHERN FA VCNTY WARM FRONTAL BOUNDARY. WITH UNIMPRESSIVE LOW LEVEL JET OVERNIGHT WOULD EXPECT CONVECTION TO WEAKEN WITH LOSS OF HEATING. NOT MUCH DRYING IN THE LOWER LEVELS SO EXPECT SIMILAR MINIMUMS TO PAST COUPLE DAYS. NORTHERN STREAM SHORT WAVE WILL SWING THROUGH S CANADIAN PRAIRIE PROVINCES MONDAY. BROAD...WEAK AREA OF LOW PRESSURE WILL REMAIN ACROSS FA ALONG WITH WEAK BOUNDARIES. WITH PRECIPITABLE H2O VALUES REMAINING ABOVE AN INCH INTRODUCED LOW POPS MONDAY AFTERNOON/EVENING WITH WAVE PASSAGE. TEMPERATURES WILL DEPEND ON DEGREE OF CLOUD COVER HOWEVER WITH NO REAL COOLING THROUGH COLUMN TEMPERATURES SHOULD STILL REACH INTO THE 80S OR CLOSE TO. REGION WILL REMAIN WITHIN CORE OF THE WESTERLIES INTO MID WEEK. CANNOT RULE ANY PASSING WAVES HOWEVER SURFACE FEATURES LOOK WEAK AS HIGH PRESSURE BEGINS TO MOVE INTO FA. FOR THIS WILL KEEP PERIOD DRY. COLUMN BEGINS COOLING TOWARDS MIDWEEK HOWEVER OVERALL SEASONAL TEMPERATURES TO CONTINUE. LONG TERM (THU-SUN)... MODELS IN GENERAL AGREEMENT ON OVERALL PATTERN. SUBTROPICAL RIDGE REMAINS ENTRENCHED OVER CENTRAL PLAINS...WITH MAINLY ZONAL PATTERN OVER THE DAKS/MN. WEAK SFC HIGH PRESSURE BEHIND COLD FRONT AT BEGINNING OF PERIOD WILL MODERATE TEMPS A BIT WITH LITTLE PCPN EXPECTED. HOWEVER...AN AREA OF LOW PRESSURE IS EXPECTED TO AFFECT THE REGION BY THE END OF THE PERIOD BRINGING WARMER TEMPERATURES...ABUNDANT MOISTURE...AND ANOTHER CHANCE FOR MEASURABLE PCPN. AVIATION... EXPECT VFR CIGS AND VSBY THROUGH THE PERIOD ALONG WITH LIGHT WINDS. SHOWERS/TSTMS ARE EXPECTED TO DEVELOP DURING THE LATE PM HOURS IN THE DVL BASIN AND SERN ND...SPREADING ACROSS THE AREA TO THE OTHER TAF SITES BY AROUND 00Z. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && MF
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND FORKS ND 634 AM CDT SUN AUG 1 2010 MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024- 026>030-038-039-049-052>054-021145- 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 COUNTY-EDDY-NELSON- GRAND FORKS-GRIGGS-STEELE-TRAILL-BARNES-CASS-RANSOM-SARGENT- RICHLAND-WESTERN WALSH COUNTY- 634 AM CDT SUN AUG 1 2010 ...SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON AND EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN NORTH DAKOTA...WEST CENTRAL AND NORTHWEST MINNESOTA. .DAY ONE...TODAY AND TONIGHT SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE SOUTHERN RED RIVER VALLEY THIS MORNING...BRINGING SOME LIGHTNING STRIKES AND BRIEF DOWNPOURS. THUNDERSTORMS WILL BEGIN TO REDEVELOP BY THIS AFTERNOON AS THE ATMOSPHERE BECOMES LESS STABLE. SOME OF THE STORMS COULD BECOME STRONG TO SEVERE...WITH LARGE HAIL AND DAMAGING WIND GUSTS POSSIBLE. A FEW TORNADOES ARE NOT OUT OF THE QUESTION. THE SEVERE THUNDERSTORMS WILL CONTINUE INTO THE EVENING HOURS BEFORE GIVING WAY TO A HEAVY RAIN THREAT...MAINLY SOUTH AND EAST OF A BEMIDJI TO VALLEY CITY LINE. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THE CHANCE FOR THUNDERSTORMS WILL LINGER INTO THE DAY ON MONDAY...WITH SOME HAIL AND WINDS POSSIBLE. ANOTHER CHANCE FOR THUNDERSTORMS WILL ARRIVE THURSDAY NIGHT AND WILL CONTINUE INTO SATURDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE REQUIRED. JR
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 729 PM CDT SUN AUG 1 2010 NDZ006-007-020130- CAVALIER ND-TOWNER ND- 729 PM CDT SUN AUG 1 2010 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN TOWNER AND NORTHWESTERN CAVALIER COUNTIES UNTIL 830 PM CDT... AT 725 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A THUNDERSTORM 31 MILES NORTHWEST OF CANDO...OR 52 MILES WEST OF LANGDON...MOVING TO THE EAST AT 20 MPH. HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THE STORM...ALONG WITH HEAVY RAIN. THE STORM WILL BE NEAR... HANSBORO AROUND 740 PM CDT. AMOURDALE AROUND 745 PM CDT. ROCKLAKE AROUND 805 PM CDT. SARLES...CLYDE AND CALVIN AROUND 830 PM 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. VOELKER
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
907 PM CDT SUN AUG 01 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0840 PM TSTM WND DMG MUNICH 48.67N 98.83W
08/01/2010 CAVALIER ND CO-OP OBSERVER
16 INCH TREES SNAPPED,POSSIBLE FUNNEL CLOUD BUT RAIN
WRAPPING PRECLUDES DEFINITIVE DETERMINATION.
&&
WBARRETTPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
954 PM CDT SUN AUG 01 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0815 PM TSTM WND DMG ROCKLAKE 48.79N 99.25W
08/01/2010 TOWNER ND CO-OP OBSERVER
10 INCH DIAMETER TREES FELLED. GARAGE PUSHED OFF
FOUNDATION. LEG OF A FERTILIZER PLANT TOPPLED OVER.
REPORTED BY ND ARB OBSERVER.
&&
WBARRETTSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 1030 PM CDT SUN AUG 1 2010 NDZ006-007-015-020415- CAVALIER ND-RAMSEY ND-TOWNER ND- 1030 PM CDT SUN AUG 1 2010 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN TOWNER...SOUTHWESTERN CAVALIER AND NORTHERN RAMSEY COUNTIES UNTIL 1115 PM CDT... AT 1025 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A THUNDERSTORM 16 MILES NORTHWEST OF CANDO...OR 45 MILES NORTHWEST OF DEVILS LAKE...MOVING TO THE SOUTHEAST AT 25 MPH. HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THE STORM...ALONG WITH HEAVY RAIN. THE STORM WILL BE NEAR... BISBEE AROUND 1035 PM CDT. ARNDT AROUND 1045 PM CDT. CONSIDINE AROUND 1050 PM CDT. CANDO AND EGELAND AROUND 1100 PM 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. MF
The Fargo/Grand Forks radar (KMVX), 172 km away, was scanning. The volume nearest the first event began at 03:57 UTC.
1 flash flood. Local standard time, as filed.
Rainfall amounts from 4 to 5 inches produced flooding to area fields and farm access roads.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2010Every state in 2010This day in weather historyWarnings in Minnesota, August 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: 239976.