Tornadoes · United States · Minnesota · 2002

F0 tornado, Bagley to Shevlin, Minnesota, August 11, 2002

From Bagley to Shevlin, this F0 tornado ran 0.2 miles across Clearwater County on August 11, 2002, touching down at 8:45 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 mphthis tornado

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

  2. F173 to 112 mph

    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
F0
Date
August 11, 2002
Touchdown
8:45 PM CDT (01:45 UTC)
Path length
0.2 miles (0.3 km)
Path width
25 yards (23 m)
Deaths
0
Injuries
0
County
Clearwater County
Touchdown point
47.500, -95.400
Lift-off point
47.500, -95.400
Record number
815

What the Weather Service recorded

The tornado made a brief touchdown in a open pasture.

A brief touchdown knocked down a few trees in a yard.

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

The warnings

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.

Issued (UTC)ExpiredProductOffice
00:51 UTC01:45 UTCSevere Thunderstorm WarningFGF
01:46 UTC02:45 UTCSevere Thunderstorm WarningFGF
01:53 UTC02:45 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 Moderate Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 00:47 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.

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), 00:00Z

1.8 hours before the tornado, 196 km from the path. August 12, 2002.

Skew-T log-pSkew-T log-p diagram, International Fa, MN at 00:00Z on 2002-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 204 joules per kilogram, CIN -162, lifted condensation level 1684 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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 2002-08-12The 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 40 square meters per square second, 0 to 6 km bulk shear 32 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
204 J/kg
Mixed-layer CIN
-162 J/kg
Surface CAPE
1628 J/kg
Mixed-layer LCL
1684 m above ground
0-6 km bulk shear
32 kt
0-1 km bulk shear
9 kt
0-1 km storm-relative helicity
40 m²/s²
0-3 km storm-relative helicity
139 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4
0-3 km lapse rate
7.3 K/km

Open this sounding in Storm Lab

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

10.2 hours after it, 196 km from the path. August 12, 2002.

Skew-T log-pSkew-T log-p diagram, International Fa, MN at 12:00Z on 2002-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 49 joules per kilogram, CIN -138, lifted condensation level 710 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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 2002-08-12The 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 70 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
49 J/kg
Mixed-layer CIN
-138 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
710 m above ground
0-6 km bulk shear
20 kt
0-1 km bulk shear
26 kt
0-1 km storm-relative helicity
70 m²/s²
0-3 km storm-relative helicity
77 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.6 K/km

Open this sounding in Storm Lab

The surface observations

Fosston (FSE), 30 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
23:58 UTC78.866.2110° 3 kt1007.5
00:00 UTC78.866.2110° 3 kt1007.5
00:18 UTC78.866.2120° 4 kt1007.5VCTS
00:38 UTC7768100° 3 kt1007.5
00:58 UTC75.268110° 4 kt1007.8VCTS
01:00 UTC75.268110° 4 kt1007.8
01:17 UTC7766.2110° 6 kt1007.1VCTS
01:38 UTC64.462.6240° 17 kt261009.5TSRA
01:58 UTC62.662.6240° 15 kt221009.8+TSRA
02:00 UTC62.662.6240° 15 kt221009.8
02:21 UTC60.857.2240° 18 kt251010.5VCTSRA
02:44 UTC60.857.2290° 10 kt141009.5-VCTSRA
02:58 UTC5957.20° 0 kt1008.8VCTSRA
03:00 UTC5957.20° 0 kt1008.8
03:18 UTC5957.240° 5 kt1007.8-VCTSRA
03:38 UTC5957.290° 4 kt1006.8-RA

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 August 11, 2002

7 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 114:00 PM CDTF4Stutsman, ND1.0300$650,000
August 118:05 PM CDTF0Mahnomen, MN0.225$10,000
August 118:20 PM CDTF0Logan, KS0.125
August 118:40 PM CDTF0Red Willow, NE0.125
August 118:55 PM CDTF0Clearwater, MN0.225
August 1110:44 PM CDTF1Ford, KS6.550
August 1111:00 PM CDTF1Hodgeman, KS0.250

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.