Tornadoes · United States · North Dakota · 2002

F1 tornado, Cummings, North Dakota, August 8, 2002

This F1 tornado ran 8.0 miles across Traill County on August 8, 2002, touching down at 7:55 PM CDT and reaching 25 yards wide. It killed nobody.

The rating scale

Tracks are drawn in the color of the rating. The Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. F040 to 72 mph

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. F173 to 112 mphthis tornado

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. F2113 to 157 mph

    Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

  4. F3158 to 206 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. F4207 to 260 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. F5261 to 318 mph

    Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

  7. Unrated

    The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

The record

Rating
F1
Date
August 8, 2002
Touchdown
7:55 PM CDT (00:55 UTC)
Path length
8.0 miles (12.9 km)
Path width
25 yards (23 m)
Deaths
0
Injuries
0
County
Traill County
Touchdown point
47.500, -97.250
Lift-off point
47.580, -97.150
Record number
271

What the Weather Service recorded

A tornado touched down near Cummings.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

The warnings

25 minutes of warning. NWS FGF issued a tornado warning for this county at 00:30 UTC, 25 minutes before the tornado touched down, in force until 01:15 UTC.

Issued (UTC)ExpiredProductOffice
22:00 UTC22:45 UTCSevere Thunderstorm WarningFGF
22:46 UTC23:30 UTCSevere Thunderstorm WarningFGF
23:44 UTC05:45 UTCFlash Flood WarningFGF
00:23 UTC01:00 UTCSevere Thunderstorm WarningFGF
00:30 UTC01:15 UTCTornado WarningFGF

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The forecast that day

The Storm Prediction Center had this point in a Slight Risk. The outlook in force was issued at 20:17 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

What forecasters said that day

The local office's own words before the tornado touched down, 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 tornado touched down at Aug 8, 3:25 PM CDT, 4 hours 30 minutes earlier.

Area forecast discussion, Aug 8, 3:25 PM CDT, 4 hours 30 minutes before
FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
325 PM CDT THU AUG 8 2002

FORECAST CHALLENGE FOR TODAY IS PRECIPITATION. LATEST SATELLITE
IMAGERY SHOWS CLOUDS MAINLY OVER ND SIDE. KMVX HAS CLUSTER OF SEVERE
THUNDERSTORMS IN DVL AREA WITH ADDITIONAL PRECIPITATION EXTENDING
ALONG W EDGE OF AREA. CURRENT MSAS SURFACE ANALYSIS SHOWS SURFACE
LOW CENTERED IN S MB...WITH FRONT EXTENDING THROUGH ND ALONG A
DVL-JMS-MBG LINE. WHEN COMPARING MSAS DATA TO MODEL
INITIALIZATIONS...NGM AND ETA BETTER MATCH THAN AVN...WITH AVN A TAD
MORE PROGRESSIVE. HOWEVER...MODELS VARY QUITE A BIT ON HOW UPPER
LEVEL LOW WILL TRAVERSE THROUGH AREA AND AMOUNTS OF QPF ACCOMPANYING
IT. CONSEQUENTLY...STUCK CLOSEST TO ETA TIMING...BUT UTILIZED AVN
FOR QPF COMPROMISE. WITH LIFTED INDICES DOWN TO -9 AND A GOOD
SURFACE MOISTURE FLUX CONVERGENCE AREA ALONG AND AHEAD OF TROF IN E
ND...EXPECT THUNDERSTORMS...SOME SEVERE WITH HEAVY RAIN TO DEVELOP
SHORTLY AND CONTINUE THROUGH MUCH OF THE EVENING. AS A RESULT...WILL
KEEP FLOOD WATCH FOR TONIGHT AND PARTS OF MN FOR FRI. IN
ADDITION...SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED FOR E ND AND
PARTS OF NW MN UNTIL 9 PM TONIGHT. UPPER LEVEL LOW FINALLY MOVES E
OF AREA SAT NIGHT...ALLOWING UPPER LEVEL RIDGE TO BRIEFLY BUILD IN
OVER AREA FOR SAT NIGHT AND SUN.

EXTENDED...ENSEMBLES AND 12Z AVN LEAN TOWARD A SLOWER SOLUTION THAN
OPERATIONAL MRF FOR UPPER LOW MOVING SOUTH THROUGH MANITOBA. UPPER
LOW WILL DRAW MUCH COOLER WEATHER INTO THE N PLAINS FOR THE FIRST
PART OF THE WEEK WITH HINTS OF +4-6C TEMPERATURES AT 850MB INVADING
THE REGION. EXPECT COOL AND SHOWERY DAY ON MON WITH LINGERING
ACTIVITY INTO TUE. SYSTEM SWINGS TOWARD THE NE BY MID WEEK WITH
GRADUAL WARMUP TO FOLLOW. TEMPERATURES WILL BE BELOW SEASONAL
AVERAGES DURING THE PERIOD.

.FGF...FLOOD WATCH FOR ALL OF AREA TONIGHT...AND FOR PARTS OF NW AND
WC MN FOR FRI. SEVERE THUNDERSTORM WATCH ALL OF E ND AND PARTS OF NW
AND WC MN UNTIL 9 PM TONIGHT.

NG

In the hours before

Local storm report, Aug 8, 7:22 PM CDT, 33 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND FORKS, ND
722 PM CDT THU AUG 8 2002

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

0305 PM    4 NW SOUTHAM              ND   .75 INCH HAIL
08/08/02   RAMSEY

0330 PM    3 W BARTLET               ND   .88 INCH HAIL
08/08/02   RAMSEY

0415 PM    8 W VALLEY CITY           ND   1.00 INCH HAIL
08/08/02   BARNES

0450 PM    FINLEY                    ND   WIND DAMAGE
08/08/02   STEELE                         BUILDING UNDER
                                          CONSTRUCTION COLAPSED.
                                          ESTIMATED 75 MPH WINDS.

0450 PM    FINLEY                    ND   .75 INCH HAIL
08/08/02   STEELE

0515 PM    COLGATE                   ND   .75 INCH HAIL
08/08/02   STEELE

0530 PM    7 E HOPE                  ND   .88 INCH HAIL
08/08/02   STEELE

0542 PM    1 S EMERADO               ND   .75 INCH HAIL
08/08/02   GRAND FORKS

0542 PM    1 S EMERADO               ND   60 MPH WIND GUST
08/08/02   GRAND FORKS

0550 PM    7 E GRAND FORKS AFB       ND   .75 INCH HAIL
08/08/02   GRAND FORKS

0555 PM    GRAND FORKS               ND   .88 INCH HAIL
08/08/02   GRAND FORKS                    @ FGF WFO.

0555 PM    GRAND FORKS               ND   59 MPH WIND GUST
08/08/02   GRAND FORKS                    @ FGF WFO.

0600 PM    6 W GRAND FORKS           ND   62 MPH WIND GUST
08/08/02   GRAND FORKS                    @ KGFK AIRPORT.

0605 PM    EAST GRAND FORKS          MN   WIND DAMAGE
08/08/02   POLK                           TREE DAMAGE, 4-5 DIA.

0625 PM    6 S BLABON                ND   .75 INCH HAIL
08/08/02   STEELE

0625 PM    6 S BLABON                ND   60 MPH WIND GUST
08/08/02   STEELE

0645 PM    6 NE HOPE                 ND   1.00 INCH HAIL
08/08/02   STEELE

The air that afternoon

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Bismarck Municip, ND (KBIS), 00:00Z

0.9 hours before the tornado, 278 km from the path. August 9, 2002.

Skew-T log-pSkew-T log-p diagram, Bismarck Municip, ND at 00:00Z on 2002-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 863 joules per kilogram, CIN -27, lifted condensation level 1927 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Bismarck Municip, ND at 00:00Z on 2002-08-09The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 20 square meters per square second, 0 to 6 km bulk shear 20 knots.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
863 J/kg
Mixed-layer CIN
-27 J/kg
Surface CAPE
1251 J/kg
Mixed-layer LCL
1927 m above ground
0-6 km bulk shear
20 kt
0-1 km bulk shear
7 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
49 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.7
0-3 km lapse rate
8.0 K/km

Open this sounding in Storm Lab

Bismarck Municip, ND (KBIS), 12:00Z

11.1 hours after it, 278 km from the path. August 9, 2002.

Skew-T log-pSkew-T log-p diagram, Bismarck Municip, ND at 12:00Z on 2002-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -66582, lifted condensation level 1410 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Bismarck Municip, ND at 12:00Z on 2002-08-09The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity -41 square meters per square second, 0 to 6 km bulk shear 39 knots.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
-66582 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1410 m above ground
0-6 km bulk shear
39 kt
0-1 km bulk shear
14 kt
0-1 km storm-relative helicity
-41 m²/s²
0-3 km storm-relative helicity
105 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.3 K/km

Open this sounding in Storm Lab

The surface observations

Grand_forks (GFK), 46 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
22:58 UTC71.662.6310° 13 kt511015.6+TSRA
23:00 UTC69.862.6300° 11 kt411015.6+TSRA
23:05 UTC6864.40° 0 kt1014.9+TSRA BR
23:09 UTC6864.4110° 4 kt1014.9+TSRA BR
23:19 UTC69.866.2130° 9 kt1014.6TSRA BR
23:32 UTC69.864.4150° 11 kt1014.6-TSRA
23:53 UTC7067110° 8 kt1014.2TS
00:22 UTC69.868160° 8 kt1013.9-RA
00:31 UTC71.668170° 10 kt1014.6VCTS -RA
00:53 UTC7268170° 16 kt1014.2VCTS
01:10 UTC71.666.2170° 10 kt1013.5-RA
01:41 UTC69.864.4160° 13 kt1014.2VCTS -RA
01:53 UTC6965160° 13 kt1014.2-TSRA
02:53 UTC7165160° 6 kt1013.9VCTS -RA

From the Iowa Environmental Mesonet's archive of airport observations.

The radar

The Fargo/Grand Forks radar (KMVX), 9 km away, was scanning. The volume nearest the touchdown began at 00:53 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

This ground now

The live radar over the trackEvery 2002 tornado in North DakotaEvery tornado in North Dakota since 1950Warnings in force in North Dakota nowThe forecast where you are

The other tornadoes of August 8, 2002

1 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 82:34 PM MDTF0Harding, SD1.025

What this means

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.