F0 tornado, Belmond, Iowa, June 6, 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 6, 1999

Touchdown

4:19 PM CDT (21:19 UTC)

Path length

0.1 miles (0.2 km)

Path width

20 yards (18 m)

Deaths

0

Injuries

0

County

Wright County

Touchdown point

42.850, -93.600

Lift-off point

42.850, -93.600

Record number

984

A cold front and dry line were approaching Iowa during the morning of the 6th. Overnight the preceding night, the dry line aloft moved into Iowa, however the dry line at the surface lagged behind by a few hundred miles. At sunrise, surface dew points were in the upper 60s to low 70s over western Iowa, while the dew point at 850 mb over Omaha had dropped to -8 degrees C. Little eastward progress occurred during the day as a strong upper level disturbance began to lift north from the Texas Panhandle. During the early afternoon skies cleared over western into central Iowa. Temperatures warmed into the upper 80s to low 90s, while at the same time temperatures in the mid levels cooled several degrees C. As a result, CAPE values were in excess of 4000 J/kg. By late afternoon, Iowa was in the rear entrance region of an upper level jet streak. Thunderstorms erupted as a result. Actually there were two short lines of convection. Both were oriented north-northeast to south-southwest and were moving northeast around 50 MPH. Severe weather developed rapidly and was mainly in the form of high winds and hail. There were several small tornadoes as well. Reports indicate that most of the tornadoes were brief spin-up tornadoes or gustnadoes. With the exception of two slightly stronger tornadoes, all of the tornadoes were very short lived F-0 tornadoes and produced little damage. A couple of the tornadoes did turn out to be a bit stronger. One in Webster County south of Otho was on the ground for a couple miles, while another was intermittently on the ground for over 10 miles in Franklin County. All of the tornadoes were over rural areas and consequently did little damage. Hail was very common with the storms as well. There were numerous reports of hail from three quarters inch up to golf ball size. One of the cells produced a two to three mile wide swath of one inch diameter hail across Kossuth County north of Algona, causing considerable crop damage. In addition to the hail, many locations reported winds of 60 to 70 MPH. High winds in Thornton lifted a steel grain bin and crushed it. In Hancock County, high winds from one of the storms blew a semi-tractortrailer over south of Corwith. The driver sustained minor injuries from broken glass. Winds were common since the storms were moving about 50 MPH themselves. Local law enforcement reported visibility reduced to under one half mile in blowing dust with several of the storms. Winds around 60 MPH swept through the Gowrie area in Webster County for example. Power was knocked out and many trees were toppled by the high winds. A barn was nearly destroyed near Stratford in Hamilton County.

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

6 minutes of warning. NWS DMX issued a tornado warning for this county at 21:13 UTC, 6 minutes before the tornado touched down, in force until 21:45 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. The outlook in force was issued at 20:19 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 Des Moines radar (KDMX), 125 km away, was scanning. The volume nearest the touchdown began at 21:20 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 1999 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

36 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.