F0 tornado, Vinton, Iowa, August 3, 1994

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

August 3, 1994

Touchdown

3:40 PM CDT (20:40 UTC)

Path length

0.1 miles (0.2 km)

Path width

20 yards (18 m)

Deaths

0

Injuries

0

County

Benton County

Touchdown point

42.170, -91.970

Record number

842

Thunderstorms were numerous over Iowa throughout the day. Several weather features caused the continual development. There was an upper level disturbance approaching from the west, while a trough of low pressure approached from the northwest. Farther northwest was an approaching arctic cold front. The atmosphere was very moist with deep moisture in place and convective available potential energy between 3000 and 3500 J-Kg-1 over much of the state. Even so, the situation was not overly conducive to severe weather. Thunderstorms moved over the west half of the state during the morning hours. The east half remained under partly sunny skies with thunderstorms erupting during the early afternoon hours, once the weak cap had broken. The storms produced heavy rainfall and some gusty winds. Only a few became severe. A severe thunderstorm moved through Winfield in Henry County, downing several trees. Another storm produced a brief microburst south of Newton in Jasper County. Many large tree limbs, up to 20 inches in diameter, were torn off. Crops were flattened in a narrow strip for about a mile downstream. Another storm produced a brief spin up tornado in Benton County. The tornado was observed by a boater as it touched down on Rogers Park Lake. It sucked up water briefly before breaking apart. One could call it a waterspout since it did occur over water, however meteorologically it had thunderstorm structure of a land event. For that reason it was listed as a tornado instead of a waterspout. During the morning, thunderstorms moved through Clarion. Lightning struck the chimney of the elementary school. Several blocks were knocked out of the top of it and the chimney was cracked all the way down to its junction with the main building.

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 Slight Risk. The outlook in force was issued at 06:12 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 live radar over the trackEvery 1994 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

3 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.