EF0 tornado, Key Largo Pt Arpt to Upper Key Largo, Florida, December 18, 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

December 18, 2009

Touchdown

5:55 PM EST (22:55 UTC)

Lifted

5:56 PM EST (22:56 UTC)

On the ground

1 minutes

Path length

0.1 miles (0.2 km)

Path width

10 yards (9 m)

Deaths

0

Injuries

0

Property damage

$5,000

County

Monroe County

Touchdown point

25.144, -80.400

Lift-off point

25.144, -80.398

Record number

0912181655-01

A supercell thunderstorm tracked northeast along the Florida Keys. The thunderstorm first produced a weak tornado at the extreme southeast tip of Key West and south Stock Island, then tracked northeast just north of Big Pine Key before crossing the Upper Florida Keys from the west-southwest at Key Largo. A second weak tornado was reported at several Florida Bay shoreline properties.

The NWS investigated a newspaper report of a tornado at Key Largo, and found the same supercell which spawned a weak tornado in the Lower Florida Keys also caused a short-lived weak tornado near Mile Marker 104 of the Overseas Highway. The tornado produced minor damage with some outdoor furniture destroyed and ornamental palm trees downed in a parking lot at a Florida Bay-side business, and porch screens blown out at a restaurant next door. Maximum winds estimated at 65 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.

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 19:51 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 Miami radar (KAMX), 52 km away, was scanning. The volume nearest the touchdown began at 22:54 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.

The live radar over the trackEvery 2009 tornado in FloridaEvery tornado in Florida since 1950Warnings in force in Florida nowThe forecast where you are

3 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.