Tornadoes · United States · Kansas · 2007

EF0 tornado, Alma, Kansas, May 1, 2007

This EF0 tornado ran 0.1 miles across Wabaunsee County on May 1, 2007, touching down at 1:50 PM CDT and reaching 50 yards wide. It killed nobody.

The rating scale

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

  1. EF065 to 85 mphthis tornado

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

  2. EF186 to 110 mph

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

  3. EF2111 to 135 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. EF3136 to 165 mph

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

  5. EF4166 to 200 mph

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

  6. EF5over 200 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
EF0
Date
May 1, 2007
Touchdown
1:50 PM CDT (18:50 UTC)
Path length
0.1 miles (0.2 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
Wabaunsee County
Touchdown point
39.035, -96.280
Lift-off point
39.035, -96.280
Record number
0705011250-01

What the Weather Service recorded

Heavy rain during the morning brought some flash flooding to parts of Pottawatomie county. Rock Creek in Louisville spilled out of its banks bringing some lowland flooding. Lowland and small stream flooding occurred over other parts of the county with a few rainfall amounts over 6 inches. By afternoon, several brief tornadoes and numerous funnel clouds were reported in a few other counties as unstable air gave rise to thunderstorms. The thunderstorms also gave locally heavy rain and some flash flooding as well.

Brief touchdown from a mini-supercell, 2 miles southeast of Interstate 70 near Alma.

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
18:58 UTC19:30 UTCTornado WarningTOP
20:04 UTC20:45 UTCTornado WarningTOP
21:31 UTC00:30 UTCFlash Flood WarningTOP

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 16:08 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.

Topeka, KS (KTOP), 12:00Z

6.8 hours before the tornado, 55 km from the path. May 1, 2007.

Skew-T log-pSkew-T log-p diagram, Topeka, KS at 12:00Z on 2007-05-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 36 joules per kilogram, CIN -148, lifted condensation level 1175 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, Topeka, KS at 12:00Z on 2007-05-01The 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 8 square meters per square second, 0 to 6 km bulk shear 19 knots.1939Sfc1 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
36 J/kg
Mixed-layer CIN
-148 J/kg
Surface CAPE
11 J/kg
Mixed-layer LCL
1175 m above ground
0-6 km bulk shear
19 kt
0-1 km bulk shear
13 kt
0-1 km storm-relative helicity
8 m²/s²
0-3 km storm-relative helicity
21 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.2 K/km

Open this sounding in Storm Lab

Topeka, KS (KTOP), 00:00Z

5.2 hours after it, 55 km from the path. May 2, 2007.

Skew-T log-pSkew-T log-p diagram, Topeka, KS at 00:00Z on 2007-05-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 444 joules per kilogram, CIN -15, lifted condensation level 842 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, Topeka, KS at 00:00Z on 2007-05-02The 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 12 square meters per square second, 0 to 6 km bulk shear 5 knots.1939Sfc1 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
444 J/kg
Mixed-layer CIN
-15 J/kg
Surface CAPE
732 J/kg
Mixed-layer LCL
842 m above ground
0-6 km bulk shear
5 kt
0-1 km bulk shear
5 kt
0-1 km storm-relative helicity
12 m²/s²
0-3 km storm-relative helicity
17 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
6.3 K/km

Open this sounding in Storm Lab

The surface observations

Manhattan (MHK), 36 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
16:52 UTC67640° 0 kt1013.9
17:45 UTC69.864.430° 7 kt1013.9
17:52 UTC716530° 7 kt1013.9
18:01 UTC71.664.420° 7 kt1013.9
18:09 UTC69.864.410° 10 kt1013.9
18:52 UTC696430° 10 kt1013.5
19:04 UTC69.862.630° 13 kt1013.5
19:24 UTC69.864.440° 11 kt1013.5
19:31 UTC69.862.630° 9 kt1013.5
19:45 UTC69.864.440° 9 kt1013.5
19:52 UTC696430° 9 kt1013.5

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

The radar

The Topeka radar (KTWX), 6 km away, was scanning. The volume nearest the touchdown began at 18:49 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
18:15 UTCFUNNEL CLOUD4 N WilseyMorris, KSNUMEROUS REPORTS OF FUNNEL CLOUDS OBSERVED BY PUBLIC AND LAW ENFORCEMENT NORTH OF WILSEY.
18:32 UTCFUNNEL CLOUD3 Se LatimerMorris, KS2 FUNNELS REPORTED NEAR LATIMER
18:50 UTCTORNADO1 N AlmaWabaunsee, KSTORNADO TOUCHED DOWN 2 MILES SOUTH OF INTERSTATE 70 NEAR ALMA.
20:07 UTCTORNADOSe Maple HillWabaunsee, KSTORNADO REPORTED ON THE GROUND...BUT HAS SINCE LIFTED.
20:37 UTCFLASH FLOODMaple HillWabaunsee, KSHIGHWAY K-30 BETWEEN INTERSTATE 70 AND MAPLE HILL CLOSED DUE TO HIGH WATER.
21:37 UTCHEAVY RAIN 4.56 Nnw St. GeorgePottawatomie, KSAMOUNT MEASURED TO HAVE FALLEN SO FAR TODAY. AN UNOFFICIAL REPORT OF 6 INCHES OF RAIN WAS REPORTED TO HAVE FALLEN AT THE HOME OF THE SPOTTERS NEIGHBOR TO THE NORTH.

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

This ground now

The live radar over the trackEvery 2007 tornado in KansasEvery tornado in Kansas since 1950Warnings in force in Kansas nowThe forecast where you are

The other tornadoes of May 1, 2007

9 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 12:20 PM CDTEF0Meade, KS0.230
May 13:50 PM EDTEF0Wood, OH0.330
May 13:05 PM CDTEF0McCulloch, TX3.330
May 13:07 PM CDTEF0Wabaunsee, KS0.150
May 13:17 PM CDTEF0Wabaunsee, KS0.150
May 13:35 PM CDTEF0McCulloch, TX1.830
May 16:05 PM EDTEF1Crawford, PA2.030$500,000
May 16:15 PM EDTEF0Mercer, PA4.0100$20,000
May 17:40 PM CDTEF0Gillespie, TX0.220

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.