F0 tornado, Berkley, Iowa, May 30, 2000

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

May 30, 2000

Touchdown

7:28 PM CDT (00:28 UTC)

Path length

0.1 miles (0.2 km)

Path width

20 yards (18 m)

Deaths

0

Injuries

0

County

Boone County

Touchdown point

41.880, -94.120

Lift-off point

41.880, -94.120

Record number

774

An explosive situation became established over Iowa and the central U.S. during the day on the 30th. A nearly stationary front extended from Wisconsin, southwest through the northwest corner of Iowa, and into northern Kansas. A round of convection moved across the state during the morning, leaving behind several outflow boundaries. The mid levels of the atmosphere were quite warm, thus convection was capped during the afternoon hours. A strong southerly flow of moist air spread into Iowa during the afternoon. Temperatures approached 100 degrees F. over southwest Iowa. Dew point temperatures reached the upper 60s to mid 70s across much of the south two thirds of the state. Thunderstorms developed at the intersection of two outflow boundaries northwest of Des Moines, and also just ahead of the stationary front. Surface based CAPE values were well over 5000 J/kg, thus the convection developed explosively. Severe weather quickly followed. There were numerous reports of hail. Most of the hail was between one inch in diameter and golf ball size. One of the cells, which happened to be the initial cell that formed at the boundary intersection, turned into a supercell. Several tornadoes were spawned by this regenerating cell. Most of the tornadoes were very weak and short lived. The exception was one fairly small tornado that touched down on the northeast side of Des Moines. This tornado tracked through mostly open area and caused little damage on its nearly 10 mile intermittent trek into Altoona. Gusty winds were reported with many of the cells, however wind speeds were not all that great in most cases. There was one report of 60 MPH winds as the storms passed through the Saylorville area in Polk County. Heavy rain fell in a couple parts of the state. One was with the supercell in Polk County, the other area of heavy rain was in Black Hawk County. Rainfall amounts in parts of these two counties were in the two to four inch range, however little more than urban and small street flooding occurred due to dry soil conditions.

Brief touchdown

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. One was issued for the county at another hour that day.

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 20:03 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.

Boone Municipal (BNW), 29 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), 37 km away, was scanning. The volume nearest the touchdown began at 00:29 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 2000 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

5 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.