Tornadoes

tornado collage

Images of tornado damage in Florida. Courtesy of Florida Memory.

Truly destructive tornadoes are most frequently reported in Florida during the spring and summer; the most powerful usually strike in spring. Florida has the dubious distinction of having a higher frequency of tornadoes per 10,000 square miles than any other state, including Oklahoma! In Florida, measured in frequency of tornadoes for every 10,000 square miles, the coast between Tampa Bay and Fort Myers has a particularly high incidence, as do the western panhandle and parts of the Atlantic Coast.

So, what is a tornado? Simply put, a tornado is a violently rotating column of air that is spawned by a severe thunderstorm. It connects from the thunderstorm to the ground and often appears to have a funnel or column shape. A tornado, one of nature's most violent storms, can develop suddenly, and have winds in excess of 250 mph.

Generally, tornadoes in Florida form

  1. along a squall line ahead of an advancing spring cold front from the North,
  2. along the squall lines in areas where masses of warm air converge,
  3. from isolated local summer thunderstorms, and/or
  4. within a hurricane.

What triggers a tornado is still not altogether clear. Tornadoes spawn inside clouds when there is great turbulence and winds of various speeds and velocities come in contact with one another. Although there is uncertainty about the triggers, meteorologists are able to identify atmospheric conditions conducive to tornadic activity.

The intensity of a tornado can be determined only after the event when survey teams from the National Weather Service can examine structural damage. After the survey is complete, the tornado is given a value from the Fujita Scale. The Fujita Scale was developed by Dr. T. Theodore Fujita and categorizes tornadoes on the basis of their intensity and area. The scale relates a tornado's damage to the fastest quarter-mile wind speed at the height of the damaged structure to determine its intensity. Over the years, problems with the initial Fujita Scale had arisen and in 2007 the new Enhanced Fujita (EF) Scale was adopted. The EF Scale helps determine the intensity of a tornado when there is no structural damage (as can happen when, for example, a tornado passes through a corn field). 


ENHANCED FUJITA (EF) SCALE
EF Number Estimated 3-Second Gust (mph) Damage
0 (Gale) 65-85 Some damage to chimneys; branches brooken off trees; shallow-rooted trees pushed over; damaged sign boards.
1 (Weak) 86-110 Surfaces peeled off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off roads.
2 (Strong) 111-135 Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars pushed over; large trees snapped or uprooted; light object missiles generated.
3 (Severe) 136-165 Roof and some walls torn off well constructed houses; trains overturned; most trees in forests uprooted Well-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated.
4 (Devastating) 166-200 Well-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated.
5 (Incredible) 200+ Strong frame houses lifted off foundations and carried considerable distances to disintegrate; automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel reinforced concrete structures badly damaged.

*Chart summarized from information supplied by the Storm Prediction Center.

Florida tornadoes

 

SIGNIFICANT TORNADOES
Date Fujita Killed Injuries Information
2/22/1998 3 25 150 The deadliest tornado of the outbreak was a category F3, that touched down initially 1 mile south of Intercession City. The tornado moved northeast at 45 mph and ripped through the town of Kissimmee killing 25 people. The hardest hit areas were the Morningside Acres mobile home community and the Ponderosa Recreational Vehicle Park. In all 8 people were killed in recreational vehicles, 15 in mobile homes, and 1 in an automobile. The tornado continued northeast and moved into Orange County 6 miles north of St. Cloud. One hundred and fifty people were injured and over 1000 structures were damaged or destroyed
3/31/1962 3 17 100 Shortly after 9 a.m. on the 31st, a tornado carved an 8-mile path through Santa Rosa County. The hardest hit area was Milton, where 130 homes were demolished in a six-block area, and extensive damage occurred at a mobile home park.
2/22/1998 3 13 36 The tornado initially set down near Longwood and moved northeast at 45 mph. The tornado passed through several neighborhoods in the southeast portion of Sanford, killing 12 people in mobile homes and injuring 70. It continued northeast and crossed into Volusia County 5 miles east of Sanford. The near 200 mph winds of the tornado damaged or destroyed 625 structures.
2/2/2007 3 13 51 The storm that produced the Lady Lake tornado re-intensified and produced a second F3 tornado in a rural area to the west-southwest of Paisley. The tornado moved east-northeast at over 50 mph toward the Lake Mack area just west of the St. Johns river. The tornado produced a ¼-mile-wide track across the Lake Mack area, destroying 86 residences and damaging 144. Many mobile homes were completely destroyed. Thirteen people died in mobile homes.
4/4/1966 4 11 530 A tornado began near Clearwater, moved across North Tampa Bay, through Carrollwood, and Temple Terrace,and then headed east-northeast to Gibsonia, Loughman, Campbell City, and Merritt Island. There is strong evidence that this tornado was on the ground from the Gulf of Mexico to the Atlantic Ocean. The greatest damage was reported from Carrollwood to Gibsonia, where numerous houses and businesses were either damaged or destroyed.
2/2/2007 3 8 25 The tornado first touched down near the southeast corner of The Villages south of Lake Miona and moved rapidly to the east-northeast at 55 mph into Lake County. A FEMA report to Sumter County emergency management officials detailed damage to 1,145 homes, with 200 destroyed during the 6 minutes the tornado was on the ground. Then, the tornado that moved out of Sumter County and crossed into Lake County just west of Lady Lake. The ¼-mile-wide F3 tornado moved across the Lady Lake area, killing 8 people and injuring 10. The tornado damaged 180 residences and destroyed 101. All of the fatalities occurred in mobile homes. Moving east-northeast at 50 MPH, the tornado lifted near Emerald Marsh Lake.
4/19/1988 3 4 18 A tornado moved from just southwest of Madison to 11 miles east-northeast of Madison. Seventeen homes were destroyed and more than 30 homes were damaged. Some commercial buildings were either destroyed or damaged. At North Florida Junior College, 3 buildings were destroyed and 9 were damaged.
5/4/1978 3 3 94 A tornado struck the High Point section of northeastern Pinellas County; destroying 6 rooms of High Point Elementary and damaging many others. Teachers and students were buried under the debris. The 3 deaths and most of the injured from this tornado were from the elementary school. A trailer park across the street from the school also sustained damage and injuries were reported.
2/7/1971 3 0 112 A pre-dawn waterspout/tornado destroyed an expensive apartment complex in Gulf Breeze.
6/17/1959 3 0 74 Around 9:50 P.M, a tornado touched down in Coral Gables, moved over the Miami business district and Biscayne Bay, and impacted the Sunny Isles area. Most of the injuries were from flying and broken glass.

*Chart summarized from information supplied by the National Climatic Data Center.