EF0 tornado, Garnavillo to Wyalusing, Iowa, May 29, 2013

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.

Rating

EF0

Date

May 29, 2013

Touchdown

5:46 PM CDT (22:46 UTC)

Lifted

5:54 PM CDT (22:54 UTC)

On the ground

8 minutes

Path length

6.4 miles (10.3 km)

Path width

10 yards (9 m)

Deaths

0

Injuries

0

Property damage

$20,000

Counties

Clayton and Grant counties

Touchdown point

42.868, -91.218

Lift-off point

42.920, -91.115

Record number

1305291646-03

A small tornado developed east of Garnavillo (Clayton County) and traveled east/northeast to the Mississippi River before crossing over into Wisconsin. This tornado was part of a larger severe weather outbreak that occurred across much of northeast Iowa during the afternoon of May 29th. These storms developed in a warm and moist airmass behind a warm front that was moving north across the Upper Midwest. In addition to the tornado, a farm east of Oelwein (Fayette County) was hit hard by straight line winds and flash flooding occurred in Protivin (Howard County).

A small tornado crossed the Mississippi River from Iowa hitting a campground just north of Bagley (Grant County). This tornado was part of a larger severe weather outbreak that occurred across much of western Wisconsin during the afternoon and evening of May 29th. These storms developed in a warm and moist airmass behind a warm front that was moving north across the Upper Midwest. In addition to the tornado, a pole barn and other structures were damaged near Whitehall (Trempealeau County) and structural damage to buildings also occurred near Richland Center (Richland County).

A pole barn was damaged and numerous trees were knocked down from east of Garnavillo to the Wisconsin state line in the Mississippi River east of Clayton.

A small tornado crossed the Mississippi River from Clayton County going through a campground north of Bagley before dissipating.

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.

The county was under a severe thunderstorm watch, issued at 19:56 UTC and running to 03:00 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 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 19:42 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.

Prairie Du Chien (PDC), 14 km from the path, in the two hours either side.

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

The La Crosse radar (KARX), 103 km away, was scanning. The volume nearest the touchdown began at 22:45 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 2013 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

25 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.