F1 tornado, Grantville to Tonganoxie, Kansas, May 11, 2000

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.

Rating

F1

Date

May 11, 2000

Touchdown

9:27 PM CDT (02:27 UTC)

Path length

24.0 miles (38.6 km)

Path width

260 yards (238 m)

Deaths

0

Injuries

0

Property damage

$2.7 million

Counties

Jefferson and Leavenworth counties

Touchdown point

39.070, -95.330

Lift-off point

39.170, -94.930

Record number

788

Thunderstorms developed rapidly south of a cold front in eastern Kansas, and then tracked eastward. While the early evening storms were primarily hail producers, one late evening storm produced a tornado that tracked across southern Leavenworth County, resulting in damage in Tonganoxie.

A tornado formed just south of Grantville and moved east for a mile over open country doing minor power line damage before dissipating.

A tornado touched down just north of Williamstown and moved east until it crossed into Leavenworth county at 2040 cst. Windows were blown out of a house north of Williamstown. East of Williamstown it struck a farmstead where 2 homes were damaged, 5 pole barns destroyed and 2 others damaged. Metal from an outbuilding was carried 100 feet and hung in a tree 10 feet above ground.

The tornado, which had formed in Jefferson County, entered southwestern Leavenworth County at around 9:40 pm CDT, 6 miles west-southwest of Tonganoxie. The tornado moved east-northeast and lifted 2 miles north of Basehor at 10:12 pm. The 16 mile long path was as wide as 1/4 mile at times, though the average was around 100 yards wide. In Leavenworth County, 200 homes were affected and six were destroyed. One apartment building suffered roof damage. Thirteen businesses were damaged, and two were destroyed. The Leavenworth County Fairgrounds in Tonganoxie suffered extensive damage, approaching a half-million dollars. Total damage was estimated by County Emergency Management officials at $2.6 million.

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

3 minutes of warning. NWS TOP issued a tornado warning for this county at 02:24 UTC, 3 minutes before the tornado touched down, in force until 02:55 UTC.

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 Storm Prediction Center had this point in a Slight Risk. The outlook in force was issued at 00:56 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 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.

Lawrence (LWC), 14 km from the path, in the two hours either side.

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

The Pleasant Hill radar (KEAX), 82 km away, was scanning. The volume nearest the touchdown began at 02:26 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.

The live radar over the trackEvery 2000 tornado in KansasEvery tornado in Kansas since 1950Warnings in force in Kansas nowThe forecast where you are

11 more were confirmed in the United States that day.

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.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.