EF1 tornado, Morse to Mechanicsville, Iowa, May 23, 2020

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 mphthis tornado

   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. 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

EF1

Date

May 23, 2020

Touchdown

12:30 PM CDT (17:30 UTC)

Lifted

12:49 PM CDT (17:49 UTC)

On the ground

19 minutes

Path length

7.0 miles (11.3 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

0

Counties

Johnson and Cedar counties

Touchdown point

41.755, -91.427

Lift-off point

41.837, -91.345

Record number

2005231130-01

5 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.

• Portion of outbuilding roof removed. Grain bin collapsed. Large tree limbs down.
• Powert poles and power lines down.
• Porch of a house destroyed.
• Damage to farm outbuildings and a machine shed.

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

Severe thunderstorms tracked across much of eastern Iowa and northwest Illinois in the early afternoon hours of May 23rd, 2020. Storms quickly intensified in an extremely favorable environment, which was the result of a warm front lifting north across the Midwest. Seven tornadoes were confirmed from this event across Iowa and Illinois.

A tornado caused outbuilding, grain bin, and tree damage at a farmstead in northeast Johnson County. The tornado then followed an intermittent northeast path for 7 miles, and crossed into Cedar County just south of the Cedar River. The tornado downed power poles east of Sutliff. The damage in Johnson County was rated as EF-0, with maximum winds around 85 mph. The tornado rating in Cedar County was EF-1, with maximum winds around 110 mph. Johnson and Cedar County Emergency Management provided assistance in completing the survey.

A tornado caused damage at a farmstead in Johnson county, and crossed into Cedar County just south of the Cedar River, around 3.5 miles NW of Cedar Bluff. The tornado downed power poles east of Sutliff. The tornado was rated as EF-0 in Johnson County, with maximum winds of 85 mph. The rating in Cedar County was EF-1, with maximum winds around 110 mph. Johnson and Cedar County Emergency Management provided assistance in completing the survey.

A tornado developed southwest of Mechanicsville shortly before 1 pm, and tracked northeast through northern Cedar County. The tornado destroyed the porch of a home just west of Mechanicsville, and caused outbuilding damage at a farmstead just south of Cedar/Jones County line. The tornado crossed into Jones County about 3.5 miles NNE of Mechanicsville before dissipating. The tornado was rated EF1 in Cedar County with maximum winds estimated around 95 mph. The tornado is designated as EF-U in Jones County as there was no observable damage. The tornado was on the ground for about 16 minutes along an intermittent 7 mile path. Assistance with the survey was provided by Cedar County Emergency Management and the Mechanicsville Fire Department.

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

12 minutes of warning. NWS DVN issued a tornado warning for this county at 17:18 UTC, 12 minutes before the tornado touched down, in force until 18:00 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 16:29 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 Quad Cities radar (KDVN), 70 km away, was scanning. The volume nearest the touchdown began at 17:27 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 2020 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

13 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.