F0 tornado, Littleton to Hazleton, Iowa, May 11, 2000

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.

Rating

F0

Date

May 11, 2000

Touchdown

8:45 PM CDT (01:45 UTC)

Path length

5.5 miles (8.8 km)

Path width

220 yards (201 m)

Deaths

0

Injuries

0

Property damage

$50,000

County

Buchanan County

Touchdown point

42.530, -91.780

Lift-off point

42.580, -91.680

Record number

866

Strong warm air advection, responsible for triggering severe thunderstorms during the morning, essentially led to a strong capping inversion during the afternoon over Eastern Iowa. Mesoanalysis during the late afternoon showed low pressure west of Des Moines, with a warm front extending eastward across Northern Iowa into Southern Wisconsin. Temperatures during the afternoon climbed well into the 90s and low 100s over Southwest Iowa. The airmass was very unstable with surface based CAPE values in excess of 4000 J/Kg. Strong shear created a favorable environment for supercell development. Convergence to the east of the surface low sufficiently eroded the cap by late afternoon, leading to explosive development of an isolated supercell near Waterloo. This supercell produced a tornado in Dunkerton in Black Hawk County, which did extensive damage. This same tornado weakened as it moved into Buchanan County. Other weak tornadoes were spawned in Buchanan County. There were also indications of scattered damage produced by downbursts with the second and fourth tornadoes. Iowa governor Tom Vilsack signed a proclamation declaring Black Hawk and Buchanan Counties disaster areas. Damage was estimated at over 1 million dollars. Most of the damage in Buchanan County came on four farms. The damage was spread along an eight mile stretch south of Hazelton. Machine sheds, grain bins and outbuildings were blown apart. Damage also occurred to farm equipment with minor damage to a few houses.

A third tornado briefly touched down 3 miles southeast of Littleton. It produced F0 damage mainly to trees with a path length of only about an 1/8 mile.

A second tornado touched down 4 miles southwest of Hazelton with a continuous path for 8 miles to a point 4 miles southeast of Hazelton. At it's maximum, it produced F1 damage with a path width of about 1000 feet. This includes damage to major power lines and a couple of farms. This was the strongest tornado in Buchanan County.

The fourth and last tornado, which was part of a family which includes the F1 event south of Hazelton, touched down 8 miles east southeast of Hazelton to 4 miles south southeast of Aurora. It was rated an F0 with a path length of 5 1/2 miles and width of about 1/8 mile.

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

15 minutes of warning. NWS DVN issued a tornado warning for this county at 01:30 UTC, 15 minutes before the tornado touched down, in force until 02:15 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.

Oelwein (OLZ), 25 km from the path, in the two hours either side.

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

The Quad Cities radar (KDVN), 141 km away, was scanning. The volume nearest the touchdown began at 01:46 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 IowaEvery tornado in Iowa since 1950Warnings in force in Iowa 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.