F1 tornado, Le Claire, Iowa, April 13, 2006

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

April 13, 2006

Touchdown

9:42 PM CDT (02:42 UTC)

Path length

1.5 miles (2.4 km)

Path width

100 yards (91 m)

Deaths

0

Injuries

0

Property damage

$60,000

County

Scott County

Touchdown point

41.600, -90.370

Lift-off point

41.600, -90.330

Record number

363

Due to the careful note taking and damage description of the individual along with actually witnessing a funnel, this is classified as a rare tornado on the cold side of the front that was initiated by a downburst.Tornado began just north of I-80 4 miles west of Le Claire at 2042 CST. The tornado traveled east northeast crossing 257th Avenue just south of 205th Street and dissipated on 205th Street about 0.5 miles east of the intersection of 257th Avenue and 205th Street at 2045 CST.The corner of a wooden roof was torn off a cattle building and boards scattered (some nailed themselves into the wall of the corn crib next to it). The entire roof was lifted and then set back down. The south cinder block wall collapsed inward on the cattle building and the north walls bowed out to the northeast from the roof lifting off. A large shed door on the east side of the corn crib next to the cattle building was torn off and flung 50 yards to the northeast. The door hit a 100 year old tree trunk and knocked it out of the ground. A window was blown out on the east end of the corn crib next to the original cattle building. The window landed on the northwest corner of the property up and over on the opposite side of farmhouse some 975-980 yards distance.Part of the steel sheeting was peeled back on the southwest corner roof of a new machine shed located to the north of the cattle building. A skylight window was sucked out of another freestanding cattle barn located to the east of the original cattle building.A wooden dog house on the porch of the farmhouse was flipped onto its roof and a power pole was knocked out a couple of miles northeast of the farm.

Rated F1

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

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.

The county was under a severe thunderstorm watch, issued at 22:33 UTC and running to 04:57 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, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 01:00 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.

The Quad Cities radar (KDVN), 19 km away, was scanning. The volume nearest the touchdown began at 02:40 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.

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

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

The live radar over the trackEvery 2006 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

17 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.