Tornadoes · United States · Minnesota · 2002

F1 tornado, Bejou, Minnesota, July 25, 2002

This F1 tornado ran 3.0 miles across Mahnomen County on July 25, 2002, touching down at 6:58 PM CDT and reaching 50 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
July 25, 2002
Touchdown
6:58 PM CDT (23:58 UTC)
Path length
3.0 miles (4.8 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
Mahnomen County
Touchdown point
47.480, -95.930
Lift-off point
47.450, -95.920
Record number
779

What the Weather Service recorded

Numerous trees were uprooted.

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

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 Jul 25, 2:10 PM CDT, 4 hours 48 minutes earlier.

Area forecast discussion, Jul 25, 2:10 PM CDT, 4 hours 48 minutes before
FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
210 PM CDT THU JUL 25 2002

FORECAST CHALLENGE WILL BE CONVECTIVE CHANCES FRIDAY NIGHT AND SATURDAY

.OVERVIEW...
LATEST SFC ANALYSIS SHOWS SECONDARY TROUGH JUST WEST OF
VALLEY...AHEAD OF SUBTLE SHORTWAVE MOVING INTO NORTHEAST ND. SOME
TOWERING CUMULUS IS TRYING TO DEVELOP NEAR TROUGH...IN AREA OF
1000J/KG CAPE AND LOWER/MID 60S DEWPOINTS. WITH AVN/ETA NOT
RUNNING...WILL UTILIZE CANADIAN MODEL WITH EXTRAPOLATION AND RUC FOR
FIRST 12 HOURS OF FORECAST.

.SHORT TERM...
WITH TROUGH AND WEAK VORT MAX...WILL INSERT ISOLATED THUNDER ALONG
AND EAST OF VALLEY THIS EVENING. CAPES APPROACH 1500 J/KG...BUT WITH
LITTLE DIRECTIONAL SHEAR DON/T ANTICIPATE AND SEVERE STORMS WITH
CONVECTION THIS EVENING. TEMPS OVERNIGHT SHOULD DROP TO NEAR 60 AS
SLIGHTLY DRIER AIR FILTERS IN. WILL ALSO KEEP PATCHY FOG MENTION
AFTER MIDNIGHT...WITH SATURATION OCCURRING WITH MINIMAL DRY AIR
ADVECTION.

.LONG TERM...
REGION REMAINS IN GENERALLY ZONAL FLOW...WITH HARD TO TIME
SHORTWAVES MOVING THROUGH FLOW. BEST CHANCE AT THUNDER APPEARS TO BE
FRIDAY NIGHT INTO SATURDAY...THEN AGAIN SATURDAY EVENING INTO SUNDAY
NIGHT. CAPES SHOULD APPROACH 3000 J/KG SATURDAY...ALONG WITH SFC
BOUNDARY...SO SOME SEVERE WEATHER EXPECTED DEPENDING ON STRENGTH OF
CAP...WHICH HAS BEEN UNDERDONE BY MODELS OF LATE. TEMPS SHOULD BE IN
THE LOW/MID 80S SATURDAY...COOLING A BIT SUNDAY TO AROUND 80.

.EXTENDED...
MODELS SHIFTING GEARS TOWARDS PROGRESSIVE AMPLIFYING LONGWAVE PATTERN
OVER CONUS. ABOVE SCENARIO SHOULD RESULT IN SIGNIFICANT WARMING
TREND BY THE MIDDLE TO LATTER PART OF NEXT WEEK OVER REGION AS
DEEPENING UPPER LEVEL TROUGH VICINITY OF WESTERN CANADA AND PACIFIC
NORTHWEST PUMPS UPPER LEVEL RIDGE OVER THE NORTHERN PLAINS. DURING
TRANSITIONAL STAGE CONVECTIVE THREAT LOOMS ON THE HORIZON FOR
MONDAY...OTHERWISE DEVELOPING PATTERN CONDUCIVE FOR INCREASING HEAT
AND HUMIDITY WITH INCREASING WARMTH IN THE MID LAYERS PRODUCING
INHIBITING CAP FOR ANY ADDITIONAL CONVECTIVE DEVELOPMENT/THREAT.

.FGF...NONE

KELLENBENZ/BERG

In the hours before

Local storm report, Jul 25, 2:26 PM CDT, 4 hours 32 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND FORKS, ND
226 PM CDT THU JUL 25 2002

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

0110 AM    1 NE HAWLEY               MN   .88 INCH HAIL 07/25/02
CLAY

0130 AM    9 S  LIDGERWOOD           ND   60 MPH TSTORM WIND
07/25/02   RICHLAND                       SHINGLES TORN FROM ROOF

0200 AM    7 N LAKE PARK             MN   1.00 INCH HAIL
07/25/02   BECKER

WJB
Local storm report, Jul 25, 5:15 PM CDT, 1 hour 43 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND FORKS, ND
515 PM CDT THU JUL 25 2002

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

0504 PM    3 NW HAUG                 MN   1.00 INCH HAIL
07/25/02   ROSEAU

BJB

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.

International Fa, MN (KINL), 12:00Z

12.0 hours before the tornado, 231 km from the path. July 25, 2002.

Skew-T log-pSkew-T log-p diagram, International Fa, MN at 12:00Z on 2002-07-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 8 joules per kilogram, CIN -127, lifted condensation level 514 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, International Fa, MN at 12:00Z on 2002-07-25The 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 87 square meters per square second, 0 to 6 km bulk shear 21 knots.193958Sfc1 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
8 J/kg
Mixed-layer CIN
-127 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
514 m above ground
0-6 km bulk shear
21 kt
0-1 km bulk shear
8 kt
0-1 km storm-relative helicity
87 m²/s²
0-3 km storm-relative helicity
126 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.4 K/km

Open this sounding in Storm Lab

International Fa, MN (KINL), 00:00Z

0.0 hours before the tornado, 231 km from the path. July 26, 2002.

Skew-T log-pSkew-T log-p diagram, International Fa, MN at 00:00Z on 2002-07-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 773 joules per kilogram, CIN -9, lifted condensation level 1237 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, International Fa, MN at 00:00Z on 2002-07-26The 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 55 square meters per square second, 0 to 6 km bulk shear 23 knots.193958Sfc1 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
773 J/kg
Mixed-layer CIN
-9 J/kg
Surface CAPE
1658 J/kg
Mixed-layer LCL
1237 m above ground
0-6 km bulk shear
23 kt
0-1 km bulk shear
12 kt
0-1 km storm-relative helicity
55 m²/s²
0-3 km storm-relative helicity
90 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.1
0-3 km lapse rate
7.3 K/km

Open this sounding in Storm Lab

The surface observations

Fosston (FSE), 18 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
00:00 UTC

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

This ground now

The live radar over the trackEvery 2002 tornado in MinnesotaEvery tornado in Minnesota since 1950Warnings in force in Minnesota nowThe forecast where you are

The other tornadoes of July 25, 2002

3 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
July 254:25 AM CDTF0Thurston, NE0.120
July 255:45 PM EDTF0Polk, FL1.040$20,000
July 256:45 PM CDTF1Polk, MN3.050$20,000

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.