EF0 tornado, Rock Rapids Muni Arp to Doon, Iowa, May 30, 2022

1. EF065 to 85 mphthis tornado

   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. 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

EF0

Date

May 30, 2022

Touchdown

2:21 AM CDT (07:21 UTC)

Lifted

2:22 AM CDT (07:22 UTC)

On the ground

1 minutes

Path length

0.5 miles (0.9 km)

Path width

60 yards (55 m)

Deaths

0

Injuries

0

County

Lyon County

Touchdown point

43.274, -96.233

Lift-off point

43.279, -96.226

Record number

2205300121-01

10 damage points were recorded along this path by NWS FSD, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 90 mph.

• This picture is looking north, would have been from strong southerly inflow.
• 2x4’s laying to the southeast, with majority of other damage laying to the east-northeast
• Picture is facing south, debris origin is thought to be from farmstead to the southeast.
• Old rotting garage with south facing doors collapsed. Photo courtesy of Osceola County EM.

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

An amplified and vigorous upper level pattern pushed several weak disturbances northeast across the region during the overnight and early morning of May 30th. With ample elevated instability on the order of 2000-2500 J/kg available and effective shear of 35 to 45 knots, storms became severe across south central South Dakota and north central Nebraska and organized into a large scale QLCS as it moved east and northeast into Minnesota and Iowa late night. Several QLCS tornadoes developed from the Sioux Falls area eastward. Widespread winds of 60 to 90 mph caused scattered tree damage, with isolated pockets of more significant structural damage. Presidential Disaster Declarations were granted to Lyon, Rock, and Nobles Counties in Minnesota for damages to public infrastructure.

A tornado spun up near the intersection of Fig Avenue and 140th Street. On a northeastward track, the tornado impacted two farmsteads around a mile apart, with significant roof damage done to outbuildings at each location, as well as destruction of a large grain bin. The tornado tracked a few hundred yards beyond the final farm before dissipating in an open field. The estimated maximum wind was 90 mph and the average path width was 75 yards.

A brief tornado developed on the south side of Doon, and traveled northeast across the southeast side of town before it dissipated at the eastern edge of town. Damage was primarily to trees, with some peripheral damage to a playset near the touchdown, and an older garage near the end of the track. The estimated maximum wind was 85 mph and the average path width was 50 yards.

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

23 minutes of warning. NWS FSD issued a tornado warning for this county at 06:58 UTC, 23 minutes before the tornado touched down, in force until 07:30 UTC.

The county was under a severe thunderstorm watch, issued at 05:05 UTC and running to 13:00 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 Enhanced Risk, with a 0.10 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 05:44 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 Sioux Falls radar (KFSD), 53 km away, was scanning. The volume nearest the touchdown began at 07:20 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 2022 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.