EF0 tornado, Shelby, Nebraska, May 21, 2024

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 21, 2024

Touchdown

4:54 AM CDT (09:54 UTC)

Lifted

4:58 AM CDT (09:58 UTC)

On the ground

4 minutes

Path length

4.1 miles (6.6 km)

Path width

75 yards (69 m)

Deaths

0

Injuries

0

Property damage

$1.0 million

County

Polk County

Touchdown point

41.303, -97.472

Lift-off point

41.326, -97.398

Record number

2405210354-01

40 damage points were recorded along this path by NWS GID and NWS OAX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 94 mph.

• Loss of siding and roof panels
• Trees topped, large branches snapped
• Pivot flipped powerlines/ poles down
• Several downed trees and broken branches

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

A couple rounds of thunderstorms brings severe hail and wind to portions of south central Nebraska during the evening of May 20th and into the early morning hours of May 21st. The first round of thunderstorms developed between 6-7PM CDT along a retreating warm front that stretched W-E along roughly the I-80 corridor between Grand Island and York. This activity consisted of several semi-discrete supercells with primarily a severe hail threat of 1 to 2 inches in diameter. The greatest concentration of severe hail occurred in Hall County from Wood River to Grand Island. The severe threat with this initial round waned with loss of daytime heating between 8-9PM CDT. ||A second round of severe weather, consisting of scattered to widespread convection along the existing W to E warm front, as well as an advancing N-S outflow from the west affected the area after midnight. Severe weather reports were generally limited to low-end severe wind (i.e. measured wind gusts 55-60 MPH), and somewhat hit and miss. The exception to this was along the Hwy 81 corridor in Fillmore and Polk Counties were wind gusts of 65-75 MPH were measured on a couple of mesonet stations. Also, a small (only 75 yds wide), weak tornado (EF-0) was surveyed in extreme NE Polk County where tree, power pole, and pivot damage was noted. The severe threat with this second round shifted east of the GID CWA by around 5AM CDT.

A brief EF0 rated tornado skirted its way across northern Polk County in the early morning hours of May 21st. The tornado damaged trees, downed power lines and poles, and overturned several irrigation pivots. The peak wind was estimated to be 80 MPH.

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.

The county was under a severe thunderstorm watch, issued at 04:34 UTC and running to 11:17 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 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 05:54 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.

Columbus Municipal (OLU), 17 km from the path, in the two hours either side.

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

The Omaha radar (KOAX), 89 km away, was scanning. The volume nearest the touchdown began at 09:52 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 NebraskaEvery tornado in Nebraska since 1950Warnings in force in Nebraska 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.