EF0 tornado, Gainsville, Kentucky, August 4, 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

August 4, 2009

Touchdown

6:55 PM CDT (23:55 UTC)

Lifted

6:57 PM CDT (23:57 UTC)

On the ground

2 minutes

Path length

1.0 miles (1.7 km)

Path width

40 yards (37 m)

Deaths

0

Injuries

1

Property damage

$35,000

County

Christian County

Touchdown point

36.899, -87.483

Lift-off point

36.892, -87.466

Record number

0908041755-01

An organized complex of thunderstorms developed ahead of a cold front as it approached southern Illinois and southeast Missouri during the hottest and most unstable time of day. Very strong instability, coupled with moderately strong mid-level winds, resulted in numerous damaging wind events. Most of the damaging winds were associated with small-scale bows that raced southeast ahead of the main storm complex.

This tornado briefly touched down twice within an area of downburst winds. The first brief touchdown, which was eyewitnessed by a trained spotter, began at the intersection of U.S. Highway 41 and the bypass (Kentucky 1682). This tornado travelled just north of the bypass for about one-half mile. Damage included two fiberglass light poles snapped at the base, several trees snapped, and large limbs broken. An additional brief touchdown occurred just east of the Pennyrile Parkway on the south side of the bypass. Damage included a roof torn off a metal storage building, which was blown north back across the highway. One trained spotter was struck by a flying piece of wood and received a badly bruised shoulder which required hospital treatment. Peak winds were estimated near 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 20:11 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 Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 20:02 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.

Fort Campbell (Aaf) (HOP), 25 km from the path, in the two hours either side.

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

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 KentuckyEvery tornado in Kentucky since 1950Warnings in force in Kentucky nowThe forecast where you are

1 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.