F0 tornado, Britt, Iowa, July 14, 2003

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

July 14, 2003

Touchdown

9:15 PM CDT (02:15 UTC)

Path length

0.2 miles (0.3 km)

Path width

30 yards (27 m)

Deaths

0

Injuries

0

County

Hancock County

Touchdown point

43.050, -93.820

Lift-off point

43.050, -93.820

Record number

1323

A weak cold front moved southeast across Iowa during the night of the 14th. The airmass was very unstable over Iowa, but also very capped. By the late afternoon, CAPE values were as high as 7700 J/kg over western Iowa as temperatures warmed in to the low to mid 90s and dew points approached 80, and the lifted index dropped to -13 C. The energy was not able to be realized for the most part because of the warm air aloft. The freezing level was 17,000 feet with a 700 mb temperature of +16 C. Thunderstorms developed over Minnesota, then back developed southwest into Iowa during the late evening hours. The strongest thunderstorms were near the Minnesota border. One of them produced a brief tornado east of Wallingsford in Emmet County. The tornado touched down briefly in a farm field about 5 miles east of town, causing little damage. A short time later, broadcast reporters filmed a brief tornado touchdown south of Britt in Hancock County. Once again, other than crop damage little damage occurred.

Brief touchdown sited by TV reporters in an open farm field.

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.

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 Moderate Risk, with a 0.15 chance of a tornado within 25 miles. The outlook in force was issued at 01:10 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 Des Moines radar (KDMX), 147 km away, was scanning. The volume nearest the touchdown began at 02:13 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 2003 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

16 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.