F0 tornado, Goldfield, Iowa, June 8, 1999

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

June 8, 1999

Touchdown

6:09 PM CDT (23:09 UTC)

Path length

0.2 miles (0.3 km)

Path width

0 yards (0 m)

Deaths

0

Injuries

0

County

Wright County

Touchdown point

42.850, -93.920

Lift-off point

42.850, -93.920

Record number

992

A strong upper level disturbance moved north-northeast into Iowa during the afternoon hours. A very unstable airmass was in place over the state with lifted indices near -10 degrees C. Surface dew points were in the low 70s as high temperatures soared into the upper 80s and 90s. This combined to produce CAPE values near 5000 J/kg. Thunderstorms erupted initially developed in more or less an east to west line. That line lifted north and as it did produced very heavy rain and some hail of three quarters of an inch to an inch in diameter. A second line formed in a more north to south orientation and moved east across the state. There were also some reports of dime size or larger hail from that line as well. Serious crop damage occurred in Hancock County southeast of Kanawha due to the hail. Crops needed to be replanted in the area. The main problem was with the intersection of the two lines. At the intersection of the two outflow boundaries from the lines a few brief tornadoes occurred. These were more like spin up tornadoes and were very short lived, causing no significant damage. One was in Wright County north of Goldfield, another Humboldt County southwest of Renwick, with yet another in Hancock County southeast of the Kanawha area. As the storms moved through the Lake Mills area in Winnebago County, high winds downed trees and caused vehicle damage. As the evening progressed, the upper level vorticity maximum was evident in the radar signature. The comma head of the precipitation passes over Black Hawk and Grundy Counties. Reports southeast of Waterloo indicated 3.76 inches of rainfall in a 90 minute period. Meanwhile, the area between Reinbeck and Wellsburg received in excess of 5 inches of rain in a 3 hour period. Normally, this amount of rain would not be all that serious, however soil conditions in that part of the state were very saturated resulting in significant runoff. Flash flooding occurred in the two counties. Numerous gravel roads were washed out over the northwest part of Butler County with widespread flooding reported between Reinbeck and Wellsburg.

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

5 minutes of warning. NWS DMX issued a tornado warning for this county at 23:04 UTC, 5 minutes before the tornado touched down, in force until 23:35 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. The outlook in force was issued at 19:46 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.

Clarion (CAV), 18 km from the path, in the two hours either side.

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

The live radar over the trackEvery 1999 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

6 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.