EF1 tornado, Grafton, Iowa, April 12, 2022

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

April 12, 2022

Touchdown

10:34 PM CDT (03:34 UTC)

Lifted

10:36 PM CDT (03:36 UTC)

On the ground

2 minutes

Path length

1.2 miles (1.9 km)

Path width

70 yards (64 m)

Deaths

0

Injuries

0

Property damage

$50,000

County

Worth County

Touchdown point

43.280, -93.067

Lift-off point

43.289, -93.047

Record number

2204122134-01

1 damage points were recorded along this path by NWS ARX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 76 mph.

• Observed in satellite data. Unable to assess trees in detail.

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

Initial storms developed within the warm sector of a surface low that tracked northwest of the area, followed by a strong cold front with associated dry line that produced a quasi-linear (QLCS) storm mode later in the evening. Several tornadoes occurred across western into northern Iowa. Initially the tornadoes were associated with supercell storms, however later storms produced QLCS tornadoes as it raced east northeast across the state. In addition to the tornadoes, hail up to tennis ball size occurred with initial super cells. The later QLCS produced hail up to golf ball sized along with damaging wind gusts over 70 mph at times.||Additionally, total rainfall in excess of 2 to 4 inches fell in a swath across areas that dealt with the severe thunderstorm and tornado warnings earlier in the event. While no flash flooding was experienced, rainfall in the Winnebago River basin above Mason City resulted in minor river flooding on April 13th, exceeding minor flood stage in the morning and receding below flood stage that evening.

Tornado developed south of Highway 9 and west of Warbler Avenue and moved northeast. The tornado encountered a farmstead on the south side of Highway 9 producing EF1 damage to trees and an outbuilding. The tornado continued northeast and remained in rural farmland the rest of its path.

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.

The county was under a tornado watch, issued at 22:11 UTC and running to 03:52 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 Moderate Risk, with a 0.15 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 01:01 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 La Crosse radar (KARX), 162 km away, was scanning. The volume nearest the touchdown began at 03:34 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

27 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.