Tornadoes · United States · Kansas · 1999

F1 tornado, Claflin, Kansas, May 10, 1999

This F1 tornado ran 5.0 miles across Barton County on May 10, 1999, touching down at 7:20 PM CDT and reaching 110 yards wide. It killed nobody, and did $100,000 of property damage.

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
May 10, 1999
Touchdown
7:20 PM CDT (00:20 UTC)
Path length
5.0 miles (8.0 km)
Path width
110 yards (101 m)
Deaths
0
Injuries
0
Property damage
$100,000
County
Barton County
Touchdown point
38.480, -98.570
Lift-off point
38.530, -98.500
Record number
875

What the Weather Service recorded

In Claflin, one farmstead sustained damage where top half of barn was destroyed, grainery destroyed, grain bin disappeared, and chicken house lost nearly 2/3 of it's roof.

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
23:48 UTC00:30 UTCSevere Thunderstorm WarningICT
00:25 UTC01:30 UTCSevere Thunderstorm WarningICT
00:35 UTC01:30 UTCTornado WarningICT

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 20:05 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.

Dodge City, (KDDC), 00:00Z

0.3 hours before the tornado, 145 km from the path. May 11, 1999.

Skew-T log-pSkew-T log-p diagram, Dodge City, at 00:00Z on 1999-05-11Temperature 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 -73433, lifted condensation level 1863 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, Dodge City, at 00:00Z on 1999-05-11The 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 75 square meters per square second, 0 to 6 km bulk shear 35 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
0 J/kg
Mixed-layer CIN
-73433 J/kg
Surface CAPE
528 J/kg
Mixed-layer LCL
1863 m above ground
0-6 km bulk shear
35 kt
0-1 km bulk shear
14 kt
0-1 km storm-relative helicity
75 m²/s²
0-3 km storm-relative helicity
137 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1
0-3 km lapse rate
7.5 K/km

Open this sounding in Storm Lab

Dodge City, (KDDC), 12:00Z

11.7 hours after it, 145 km from the path. May 11, 1999.

Skew-T log-pSkew-T log-p diagram, Dodge City, at 12:00Z on 1999-05-11Temperature 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 -79948, lifted condensation level 1327 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, Dodge City, at 12:00Z on 1999-05-11The 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 -109 square meters per square second, 0 to 6 km bulk shear 53 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
-79948 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1327 m above ground
0-6 km bulk shear
53 kt
0-1 km bulk shear
7 kt
0-1 km storm-relative helicity
-109 m²/s²
0-3 km storm-relative helicity
187 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.7 K/km

Open this sounding in Storm Lab

The surface observations

Great_bend (GBD), 33 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
22:35 UTC7755.4210° 3 kt1002.7
22:55 UTC75.257.2230° 5 kt1002.7
23:15 UTC75.257.2260° 5 kt1002.7
23:35 UTC7757.2290° 8 kt1002.7
23:55 UTC75.257.2300° 9 kt1002.4
00:15 UTC75.255.4330° 14 kt171002
00:35 UTC73.455.4330° 7 kt1003
00:55 UTC71.655.4350° 11 kt1003
01:15 UTC71.655.4350° 12 kt161003.4
01:35 UTC69.855.4350° 8 kt1004.1
01:55 UTC6853.6350° 6 kt141004.4
02:15 UTC6853.660° 4 kt1004.4

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

The radar

The Wichita radar (KICT), 134 km away, was scanning. The volume nearest the touchdown began at 00:18 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 1999 tornado in KansasEvery tornado in Kansas since 1950Warnings in force in Kansas nowThe forecast where you are

The other tornadoes of May 10, 1999

9 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 103:11 AM CDTF0Adair, OK0.550$1,000
May 107:50 AM CDTF1Tyler, TX4.550$50,000
May 107:55 AM CDTF0Hardin, TX2.050$50,000
May 107:55 AM CDTF0Jasper, TX1.00$10,000
May 108:05 AM CDTF0Jasper, TX2.00$20,000
May 108:10 AM CDTF1Jasper, TX3.050$100,000
May 108:40 AM CDTF0Newton, TX2.00$30,000
May 107:43 PM EDTF0Wayne, GA0.110$1,000
May 108:16 PM CDTF0Rice, KS1.00

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.