EF1 tornado, Tabor, Iowa, December 15, 2021

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

December 15, 2021

Touchdown

4:14 PM CST (22:14 UTC)

Lifted

4:23 PM CST (22:23 UTC)

On the ground

9 minutes

Path length

10.0 miles (16.0 km)

Path width

100 yards (91 m)

Deaths

0

Injuries

0

County

Mills County

Touchdown point

40.920, -95.750

Lift-off point

40.920, -95.750

Record number

2112151614-01

59 damage points were recorded along this path by NWS OAX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF2. The highest wind the damage implies is 122 mph.

• Large transmission lines down
• Right next to lake Moved a lot of water Golf ball sized hail Homeowner had visual of tornado
• 60-70 foot oak trees uploaded.
• Partial loss of grain storage on top of barn. 12 ft door dented. Collapse of 3 car garage.

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

A low pressure system brought strong (both thunderstorm, and non-thunderstorm) winds, tornadoes, dust, snow, and record temperatures into eastern Nebraska and western Iowa. The event was determined to be a derecho meeting the criteria of wind damage.

The tornado began in the hills and rough terrain near Pease Rd and Quigg Ave, and traveled quickly northeast along the 10 mile track, lasting approximately 9 minutes. The first few miles of the tornado track were intermittent, with occasional evidence of a narrow track of damage and some substantial damage to outbuildings and trees. The damage became much more consistent as the tornado approached US Highway 275 where it damaged several outbuildings, including destruction of a well-constructed metal buildings with wooden frame. Security camera footage at this location supported the likelihood of this being caused by a tornado due to sudden directional and vertical shifts in wind which the removal of the roof and walls was completed in only 1 to 2 seconds. The tornado track continued northeast where it caused substantial tree damage, destroyed two sheds, caused minor damage to homes and snapped numerous power poles. Even at this location where the damage footprint was relatively wide, the individual tornado vortices were small, with a significant swath of wind along its eastern flank. The tornado continued north with gradually decreasing damage intensity and sporadic nature of damage.

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

13 minutes of warning. NWS OAX issued a tornado warning for this county at 22:01 UTC, 13 minutes before the tornado touched down, in force until 22:15 UTC.

The county was under a tornado watch, issued at 19:23 UTC and running to 23:19 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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 19:28 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.

Plattsmouth (PMV), 14 km from the path, in the two hours either side.

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

The Omaha radar (KOAX), 68 km away, was scanning. The volume nearest the touchdown began at 22:15 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 2021 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

124 more were confirmed in the United States that day.

All 125 of them

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.