F0 tornado, Greene, Iowa, May 26, 2005

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 26, 2005

Touchdown

4:28 PM CDT (21:28 UTC)

Path length

0.2 miles (0.3 km)

Path width

25 yards (23 m)

Deaths

0

Injuries

0

County

Butler County

Touchdown point

42.870, -92.800

Lift-off point

42.870, -92.800

Record number

82

Thunderstorms developed during the mid to late afternoon hours and persisted into the evening. A weak trough of low pressure moved through the state during the afternoon setting off the first line of thunderstorms. A cold front dropping south through South Dakota formed another line of thunderstorms to the northwest. These storms raced southeast into the state at nearly 50 kts. The airmass was fairly unstable as a closed upper level low was settling into the area and the cold pool was in place aloft. Freezing levels were in the 8000 to 8500 foot range. The Lifted Index was around -5 by late afternoon with 800-1000 J/kg of CAPE. The airmass was quite dry in the low levels with soundings showing an inverted "V" type structure in a unidirectional profile. Considerable virga was reported with most of the storms producing 45 to 55 MPH winds as they passed. A few produced small hail, and one produced a tornado that touched down briefly in a rural area of Butler County. Damage was spotty with small limbs being taken down. High winds tore a stop sign out at the base in Dallas County at Woodward. Trees were downed in the city of Boone in Boone County. The storms weakened quite rapidly once sunset occurred.

Brief touchdown in open field south of town.

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 20:11 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 Des Moines radar (KDMX), 148 km away, was scanning. The volume nearest the touchdown began at 21:28 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 2005 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

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.