EF2 tornado, Superior, Nebraska, June 20, 2010

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 mph

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. EF2111 to 135 mphthis tornado

   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

EF2

Date

June 20, 2010

Touchdown

7:50 PM CDT (00:50 UTC)

Lifted

7:55 PM CDT (00:55 UTC)

On the ground

5 minutes

Path length

1.5 miles (2.4 km)

Path width

1,300 yards (1189 m)

Deaths

0

Injuries

0

County

Nuckolls County

Touchdown point

40.024, -98.080

Lift-off point

40.018, -98.053

Record number

1006201850-01

Much like the previous day, most severe weather focused south of the Nebraska and Kansas border on this Sunday afternoon and evening. However, one severe storm crept just far enough north of the state line to produce a damaging EF2 tornado in the community of Superior in southern Nuckolls County. ||The storm complex that eventually produced this tornado initially developed across Northwest Kansas in the vicinity of a nearly stationary east-west surface front, as a subtle mid-level shortwave ejected from a large-scale western United States trough. As these storms snuck into far South Central Nebraska out of North Central Kansas, the synoptic environment was quite supportive of severe weather, featuring deep-layer wind shear of 40 knots, and MLCAPE values around 3500 J/kg. The low-level shear environment was also favorable for tornadoes, with 0-1 km shear values around 25 knots, and 0-1 km storm relative helicity of at least 300 m2/s2. The storm that produced the Superior tornado was essentially an embedded supercell on the north end of a squall line, associated with a bookend vortex that first developed within the line in North Central Kansas. ||Around the same time as the Superior tornado, a separate area of strong to severe storms flared up several counties to the north, resulting in a quarter-sized hail report from Valley County.

The most significant damage was confined to the city limits of Superior. There was widespread tree damage, along with a warehouse building and several small buildings being destroyed and a number of snapped power poles. On the southeast edge of town, railroad cars were overturned.

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

11 minutes of warning. NWS GID issued a tornado warning for this county at 00:39 UTC, 11 minutes before the tornado touched down, in force until 01:07 UTC.

The county was under a tornado watch, issued at 20:10 UTC and running to 04:00 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 Moderate Risk, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 19:58 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 Grand Island radar (KUEX), 46 km away, was scanning. The volume nearest the touchdown began at 00:49 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 2010 tornado in NebraskaEvery tornado in Nebraska since 1950Warnings in force in Nebraska nowThe forecast where you are

8 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.