F1 tornado, Ringsted, Iowa, June 11, 2004

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

June 11, 2004

Touchdown

3:50 PM CDT (20:50 UTC)

Path length

6.0 miles (9.7 km)

Path width

200 yards (183 m)

Deaths

0

Injuries

0

Property damage

$10,000

County

Emmet County

Touchdown point

43.300, -94.530

Lift-off point

43.380, -94.500

Record number

1284

A very unstable situation took shape over Iowa during the day on the 11th. A nearly stationary frontal boundary extended nearly east to west across the state along U.S. Highway 20, or roughly from Fort Dodge to Waterloo. Very unstable air was to the south of the front with dew point temperatures in the low to mid 70s common. By early afternoon, CAPE values were near 5000 J/KG with lifted indices in the -10 to -12 C. range. A dry line advanced east toward the state along with the passage of a short wave lifting northeast across the area. Thunderstorms fired along the triple point by the early afternoon hours in northwest Iowa. The storms became severe very quickly and produced tornadoes as the sounding profile became very favorable. In addition, significant mid level cooling took place as 700 mb temperatures fell several degrees during the day. Most of the storms remained over the north third of the state with numerous reports of tornadoes. The bulk of the tornadoes progressed southeast from northwest Iowa into the central counties of the state as the afternoon turned into evening. For the most part, the tornadoes were quite small with only a few remaining on the ground for more than a few tenths of a mile. Two tornadoes in Palo Alto and Emmet Counties were on the ground for a significant period of time, however they tracked over open country. There were several tornadoes in Webster County. Most of them were also small and did little damage, however one tornado near Otho hit two farmsteads there causing considerable damage. One farmstead was nearly destroyed, including significant damage to the house. Hail was common with the storms with much of it in the three quarter to one and one quarter inch diameter range. There were a few golf ball size hail reports in Webster and Hamilton Counties, and one tennis ball size hail report in Stratford in Hamilton County. Spotty reports of high were were received. Winds were in the 60 to 70 MPH range. Rainfall became a problem in a couple areas. In Kossuth County rainfall of 2 to over 3 inches fell in under 2 hours causing flooding around the County. Several roads became flooded, including Iowa Highway 9 and U.S. Highway 169. Very heavy rain in the 2 to 4 inch range fell in Hamilton County during a 2 hour period. This caused considerable flooding in the county, especially over the northwest half. There was one high wind event. In what turned out to be a high wind event occurred in Marion County. A 60 MPH wind was recorded in Pella. The event was in the wake of the line of thunderstorms and actually effected a several county area with winds of 40 to 50 MPH. Temperatures shot up 9 degrees in a few minutes at the Des Moines Airport as a 51 MPH wind gust pushed the temperature up to 90 during the mid evening hours.

Tonado tracked through open country with little damage reported.

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

26 minutes of warning. NWS DMX issued a tornado warning for this county at 20:24 UTC, 26 minutes before the tornado touched down, in force until 21:20 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 Moderate Risk, with a 0.15 chance of a tornado within 25 miles. The outlook in force was issued at 16:31 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 Sioux Falls radar (KFSD), 181 km away, was scanning. The volume nearest the touchdown began at 20:50 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 2004 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

37 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.