EF0 tornado, Kenwood to Knox City, Missouri, May 13, 2009

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 13, 2009

Touchdown

6:33 PM CDT (23:33 UTC)

Lifted

6:48 PM CDT (23:48 UTC)

On the ground

15 minutes

Path length

9.2 miles (14.9 km)

Path width

200 yards (183 m)

Deaths

0

Injuries

0

County

Knox County

Touchdown point

40.210, -92.268

Lift-off point

40.199, -92.094

Record number

0905131733-01

A strong cold front moved south across the region, triggering strong to severe thunderstorms. Several tornadoes were reported, as well as large hail and damaging winds.

A tornado touched down about a mile northeast of Kenwood and traveled to the east. Numerous trees were sheared, twisted and snapped. Also, several outbuildings were damaged with displaced roofs, impacted sides and sheet metal thrown up to half a mile away. The greatest damage was along a stretch of Highway 15 about 2.4 miles north of Edina and along County Roads 155 and 159. Also, numerous power poles were snapped. The tornado lifted and dissipated about 4.5 miles east northeast of Edina.

A tornado touched down about 3.5 miles northwest of Knox City and traveled to the east. Two outbuildings sustained major damage with a displaced roof to one of the buildings and the other sustained major damage to one of its walls. Numerous tree tops were twisted, torn and/or snapped off. The most severe damage was along County Road 164, about half a mile south of Route AA. The tornado lifted and dissipated about 2.5 miles north northeast of Knox City.

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

38 minutes of warning. NWS LSX issued a tornado warning for this county at 22:55 UTC, 38 minutes before the tornado touched down, in force until 00:00 UTC.

The county was under a tornado watch, issued at 19:40 UTC and running to 03:00 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 20:01 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 Quad Cities radar (KDVN), 206 km away, was scanning. The volume nearest the touchdown began at 23:32 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 2009 tornado in MissouriEvery tornado in Missouri since 1950Warnings in force in Missouri nowThe forecast where you are

19 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.