EF1 tornado, Lomax to Pomona, Kansas, May 21, 2011

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

May 21, 2011

Touchdown

10:43 PM CDT (03:43 UTC)

Lifted

10:52 PM CDT (03:52 UTC)

On the ground

9 minutes

Path length

2.9 miles (4.7 km)

Path width

100 yards (91 m)

Deaths

0

Injuries

0

Counties

Osage and Franklin counties

Touchdown point

38.577, -95.533

Lift-off point

38.584, -95.481

Record number

1105212143-01

Supercell thunderstorms developed in advance of a cold front and dryline during the late afternoon of Saturday May 21st. Several of the supercell thunderstorms produced tornadoes including at least 2 brief touchdowns in Topeka. The strongest tornado was rated an EF3 and hit the town of Reading Kansas. In all there were 8 tornadoes across Northeast Kansas that evening. There was one fatality which occurred in the town of Reading where a man was killed when his mobile home was destroyed. There were 5 injuries that required treatment in Reading. The supercells also produced huge hailstones with some reported to be the size of softballs and numerous reports of baseball size hail in and around Topeka.

A tornado developed just west of Quenemo touching down on the west side of town. It destroyed two structures both garages producing winds around 90 mph. The damage path continued east to around 2.5 miles southwest of Pomona in Franklin County where only minor tree damage was noted.

This segment is the extension of the tornado that hit Quenemo in Osage county and weakened as it moved into Franklin County. Only sporadic tree damage was noted in Franklin County as the tornado weakened before dissipating.

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

31 minutes of warning. NWS TOP issued a tornado warning for this county at 03:12 UTC, 31 minutes before the tornado touched down, in force until 04:00 UTC.

The county was under a severe thunderstorm watch, issued at 20:45 UTC and running to 06:00 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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 01:03 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 Topeka radar (KTWX), 78 km away, was scanning. The volume nearest the touchdown began at 03:43 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 2011 tornado in KansasEvery tornado in Kansas since 1950Warnings in force in Kansas nowThe forecast where you are

17 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.