Unrated tornado, Lisbon to Massillon, Iowa, May 24, 2024

1. EF065 to 85 mph

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. EF186 to 110 mph

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. EF2111 to 135 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. EF3136 to 165 mph

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. EF4166 to 200 mph

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. EF5over 200 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. Unratedthis tornado

   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

Unrated

Date

May 24, 2024

Touchdown

7:20 AM CDT (12:20 UTC)

Lifted

7:32 AM CDT (12:32 UTC)

On the ground

12 minutes

Path length

11.0 miles (17.7 km)

Path width

10 yards (9 m)

Deaths

0

Injuries

0

Counties

Cedar and Linn counties

Touchdown point

41.862, -91.382

Lift-off point

41.880, -91.170

Record number

2405240620-01

6 damage points were recorded along this path by NWS DVN, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 110 mph.

• Report of damage to trees and power powers consistent with rotating mesocyclone on radar just south of Solon. Rated EF-0 with max winds around 85 mph. No injuries reported.
• A trained spotter reported a tornado north of Sutliff in far southeast Linn County. Public video also showed a tornado south and east of Mechanicsville, IA. There was no known damage to assign a rating, so the tornado is classified as an EF-Unknown.
• Grain bin blown off foundation, multiple trees snapped, power poles snapped.

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

A long-lasting complex of severe thunderstorms, known as a derecho, tracked from central Nebraska through northwest Illinois during the late night hours May 23rd, to the morning of May 24th. This resulted in frequent wind damage reports and embedded tornadoes. There were 16 tornadoes confirmed in the NWS Quad Cities warning area. The four strongest tornadoes all had maximum winds near 110 mph (EF1), and those were the Delta, IA; Wellman to Frytown, IA; Bennett to Lowden, IA; and Coyne Center, IL tornadoes. This was the most tornadoes in a single event for the NWS Quad Cities warning area since the March 31, 2023 outbreak.

A trained spotter reported a tornado north of Sutliff in far southeast Linn County. Public video also showed a tornado south and east of Mechanicsville, IA. There was no known damage to assign a rating, so the tornado is classified as an EF-Unknown.

A trained spotter reported a tornado north of Sutliff in far southeast Linn County. Public video also showed a tornado south and east of Mechanicsville, IA. There was no known damage to assign a rating, so the tornado is classified as an EF-Unknown.

A tornado re-developed southwest of Bennett, IA, and tracked very rapidly northeast, causing sporadic tree and outbuilding damage. The tornado then struck a farmstead just west of Lowden, where it blew a grain bin off its foundation, and snapped multiple trees and power poles. The tornado was rated EF-1 with max winds around 110 mph. There were no injuries reported.

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

18 minutes of warning. NWS DVN issued a tornado warning for this county at 12:02 UTC, 18 minutes before the tornado touched down, in force until 12:45 UTC.

The county was under a severe thunderstorm watch, issued at 07:45 UTC and running to 15:00 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, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 05:52 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.

Iowa City (IOW), 34 km from the path, in the two hours either side.

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

The Quad Cities radar (KDVN), 64 km away, was scanning. The volume nearest the touchdown began at 12:20 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.

Local storm reports within 60 km of the path, in the three hours either side.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

The live radar over the trackEvery 2024 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

42 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.