EF1 tornado, Indian Rocks Beach to (Pie)St Pete/Clrwate, Florida, March 31, 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

March 31, 2011

Touchdown

11:04 AM EDT (15:04 UTC)

Lifted

11:05 AM EDT (15:05 UTC)

On the ground

1 minutes

Path length

0.1 miles (0.1 km)

Path width

30 yards (27 m)

Deaths

0

Injuries

0

Property damage

$750,000

County

Pinellas County

Touchdown point

27.872, -82.851

Lift-off point

27.872, -82.850

Record number

1103310904-01

A stalled frontal boundary was in place across central Florida. As the boundary began to lift north drawing in abundant warm moist air over the area, an upper level disturbance moved over the area and a squall line developed and quickly moved across the northern half of the area. Several areas of damaging winds and a tornado resulted from this fast moving line on March 30th. The warm front continued to lift north over northern Florida as a developing low pressure system shifted into the northeastern Gulf of Mexico. As this system moved across northern Florida, the cold front pushed into the local area and another series of squall lines moved across the area through the day on March 31st. Several tornadoes and areas of damaging winds occurred across the greater Tampa Bay area.

A waterspout moved onshore as a tornado and destroyed the second floor of a 3,600 square foot multiple occupancy home. Power lines and poles were snapped adjacent to the home. The tornado lifted before reaching the intercostal.

Power poles and lines were snapped, with at least 10 trees down in the area. Roof debris from industrial buildings was spread along the path. Monetary damage is a conservative estimate.

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 tornado watch, issued at 10:00 UTC and running to 16:47 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 12:30 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 Tampa radar (KTBW), 48 km away, was scanning. The volume nearest the touchdown began at 15:06 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 FloridaEvery tornado in Florida since 1950Warnings in force in Florida 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.