Tornadoes · United States · North Dakota · 2006

F0 tornado, Stirum, North Dakota, April 28, 2006

This F0 tornado ran 2.5 miles across Sargent County on April 28, 2006, touching down at 4:35 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 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
April 28, 2006
Touchdown
4:35 PM CDT (21:35 UTC)
Path length
2.5 miles (4.0 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
Sargent County
Touchdown point
46.250, -97.800
Lift-off point
46.230, -97.750
Record number
431

What the Weather Service recorded

Brief and intermittent touchdowns occurred along the damage track through open fields. The wall cloud structure continued east and passed over Gwinner around 1620 CST. Dust was observed to swirl up into the wall cloud from the top of the Gwinner grain elevator.

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

The warnings

18 minutes of warning. NWS FGF issued a tornado warning for this county at 21:17 UTC, 18 minutes before the tornado touched down, in force until 22:00 UTC.

Issued (UTC)ExpiredProductOffice
21:01 UTC22:00 UTCSevere Thunderstorm WarningFGF
21:17 UTC22:00 UTCTornado WarningFGF
22:01 UTC23:00 UTCSevere Thunderstorm WarningFGF
23:00 UTC23:45 UTCSevere Thunderstorm WarningFGF
23:40 UTC00:45 UTCSevere Thunderstorm 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 General Thunderstorms Risk. The outlook in force was issued at 20:05 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.

Aberdeen, SD (KABR), 12:00Z

9.6 hours before the tornado, 157 km from the path. April 28, 2006.

Skew-T log-pSkew-T log-p diagram, Aberdeen, SD at 12:00Z on 2006-04-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 3 joules per kilogram, CIN -108, lifted condensation level 961 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, Aberdeen, SD at 12:00Z on 2006-04-28The 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 22 square meters per square second, 0 to 6 km bulk shear 18 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
3 J/kg
Mixed-layer CIN
-108 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
961 m above ground
0-6 km bulk shear
18 kt
0-1 km bulk shear
9 kt
0-1 km storm-relative helicity
22 m²/s²
0-3 km storm-relative helicity
57 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.0 K/km

Open this sounding in Storm Lab

Aberdeen, SD (KABR), 00:00Z

2.4 hours after it, 157 km from the path. April 29, 2006.

Skew-T log-pSkew-T log-p diagram, Aberdeen, SD at 00:00Z on 2006-04-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 158 joules per kilogram, CIN -21, lifted condensation level 1828 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, Aberdeen, SD at 00:00Z on 2006-04-29The 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 42 square meters per square second, 0 to 6 km bulk shear 26 knots.1939587897117Sfc1 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
158 J/kg
Mixed-layer CIN
-21 J/kg
Surface CAPE
402 J/kg
Mixed-layer LCL
1828 m above ground
0-6 km bulk shear
26 kt
0-1 km bulk shear
11 kt
0-1 km storm-relative helicity
42 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
8.8 K/km

Open this sounding in Storm Lab

The surface observations

Sisseton (8D3), 88 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
19:56 UTC6250130° 9 kt1012.9
20:56 UTC6550120° 10 kt1012.5
21:56 UTC6450130° 13 kt1011.9
22:56 UTC6352150° 17 kt221012.2

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

The radar

The Aberdeen radar (KABR), 100 km away, was scanning. The volume nearest the touchdown began at 21:35 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.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
20:43 UTCTORNADO9 Se MarionLamoure, NDON GROUND UNTIL 345 PM THEN DISSIPATED.
21:00 UTCHAIL 0.754 E LitchvilleBarnes, ND
21:04 UTCTORNADO11 Ne La MoureLamoure, NDLAMOURE COUNTY SHERIFF REPORTS TORNADO LIFTED AND DROPPED BACK DOWN. CYCLING OF TORNADO UP AND DOWN CONTINUED AT 410 PM.
21:04 UTCTORNADO9 Se MarionLamoure, NDON GROUND UNTIL 345 PM THEN DISSIPATED.
21:23 UTCHAIL 0.755 S EnglevaleRansom, ND
21:35 UTCTORNADO2 N StirumSargent, NDBRIEF AND INTERMITTENT TOUCHDOWNS WERE OBSERVED ALONG A 2.5 MILE TRACK THROUGH OPEN FIELDS TO NEAR 5W GWINNER BY 445 PM. THE WALL CLOUD STRUCTURE CONTINUED EAST AND PASSED OVER GWINNER AROUND 520 PM. DUST WAS OBSERVED TO
21:45 UTCHAIL 0.882 Wnw StirumSargent, ND
21:58 UTCHAIL 0.88La MoureLamoure, NDSHERIFF AT LAMOURE REPORTED NICKEL AND DIME SIZE HAIL.
22:07 UTCHAIL 14 W FormanSargent, ND
22:20 UTCHAIL 0.75GwinnerSargent, ND
23:13 UTCHAIL 0.759 S CayugaSargent, NDHAILED FROM 613 PM TO 623 PM CDT.
23:20 UTCTSTM WND DMG7 E MilnorSargent, NDSEVERAL 4-6 INCH TREE BRANCHES WERE BROKEN OFF ALONG THE SARGENT AND RANSON COUNTY LINE. TREES WERE IN EARLY LEAFING STAGES.
23:20 UTCTSTM WND DMG7 S McleodRansom, NDSEVERAL 4-6 INCH TREE BRANCKES WERE BROKEN OFF IN SHELTER BELTS NEAR THE SARGENT AND RANSOM COUNTY LINE. TREES WERE IN EARLY LEAFING STAGES.
23:57 UTCHAIL 0.757 S GeneseoSargent, NDHAIL FELL ALONG THE SARGENT AND RICHLAND COUNTY LINE.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2006 tornado in North DakotaEvery tornado in North Dakota since 1950Warnings in force in North Dakota nowThe forecast where you are

The other tornadoes of April 28, 2006

9 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 283:40 PM CDTF0LaMoure, ND0.425
April 284:04 PM CDTF0LaMoure, ND0.560
April 285:25 PM CDTF0Stonewall, TX0.150
April 286:02 PM CDTF0Greer, OK0.440
April 289:18 PM CDTF0Lampasas, TX0.125
April 289:38 PM CDTF0Wise, TX0.125
April 289:45 PM CDTF1Wise, TX0.440$20,000
April 2811:05 PM CDTF0Denton, TX0.210
April 2812:20 AM CDTF1McLennan, TX0.850$200,000

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.