EF0 tornado, Aurora, Nebraska, May 2, 2021

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 2, 2021

Touchdown

7:51 PM CDT (00:51 UTC)

Lifted

7:56 PM CDT (00:56 UTC)

On the ground

5 minutes

Path length

0.9 miles (1.5 km)

Path width

150 yards (137 m)

Deaths

0

Injuries

0

Property damage

$45,000

County

Hamilton County

Touchdown point

40.840, -97.991

Lift-off point

40.853, -97.997

Record number

2105021851-02

7 damage points were recorded along this path by NWS GID, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 75 mph.

• Crossing Highway 14 south of Aurora. Video evidence.
• Dozen or so roll up door in storage unit damaged. One larger overhead door blown out.
• Large garage door on what side buckled.
• Estimated start point of tornado.

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

Slow moving front brought severe thunderstorms, including landspouts, and heavy rain to portions of south central Nebraska during the evening of May 2nd. A line of thunderstorms blossomed along a stationary front between 6-8PM CDT from southern Gosper County E to Adams County, then NE to Polk County. Once this activity developed, it remained nearly stationary until around 10PM CDT when an upper level disturbance arrived from the W and began to nudge convection to the E and SE. The primary hazard with the initial convection was landspout tornadoes. A total of four landspout tornadoes were observed: one in Kearney County, two in Hamilton County, and one in Polk County. Landspout tornadoes are often very weak and cause little to no damage. These landspouts generally fall into that category, but two of them did cause at least minor damage. Most notable was the landspout that occurred near Hwy 14 just S of Aurora. Not only was it very photogenic, but it also caused damage to a storage building and downed a power line. Other severe reports were limited to severe wind gust in Furnas County, and a large hail report in Kearney County. By late evening and into the overnight, the main threat turned to flash flooding due to the stationary/nearly-stationary nature of the thunderstorms. The heaviest rainfall amounts ranged from 3 to 6 inches and flash flooding was reported in Kearney, Adams, and Hamilton Counties. Impacts ranged from flooded streets, underpasses, and rural roads, to water in some basements in Aurora. Thunderstorms weakened considerably by midnight and lingering rain showers ended by dawn on the morning of the 3rd.||The landspout tornadoes developed within a zone of favorable juxtaposition of steep low level lapse rates, moderate low level instability, weak deep layer shear, and high ambient surface vorticity associated with the stalled surface boundary. Heavy rainfall was supported by aforementioned extremely slow storm motions, as well as seasonably high deep layer moisture.

This landspout moved north-northwest for approximately 1 mile before diminishing roughly as it crossed Highway 14 just south of Aurora. The main observable damage was damage to storage building roll-up doors, a couple of larger overhead doors and a downed power line. The treeline near the start of the tornado had evidence of cornstalks lofted up into the trees and power lines.

This landspout was rated an unknown EF scale and unknown wind speed because of the lack of observable damage. The location was estimated based on pictures and videos.

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 22:46 UTC and running to 03:55 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 Marginal Risk. The outlook in force was issued at 19:43 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.

Aurora (AUH), 5 km from the path, in the two hours either side.

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

The Grand Island radar (KUEX), 70 km away, was scanning. The volume nearest the touchdown began at 00:51 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 NebraskaEvery tornado in Nebraska since 1950Warnings in force in Nebraska nowThe forecast where you are

26 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.