By now, you have probably seen the devastation in the Midwest from the latest tornado outbreak from what has been a hyper-active spring severe weather season. As of this writing, the death toll in Joplin, Missouri stands at 126 souls; making this the single deadliest event since modern record keeping began in 1950.
Because the Joplin twister had winds in excess of 200 mph, wind engineers and meteorologists have upgraded the storm to an EF5, on the Enhanced Fujita scale, the strongest of the strong. These types of tornadoes generally comprise less than 1% of all tornadoes in any given season. This year is different. We have already witnessed several “super tornadoes,” such as the EF5 Hackleburg, AL tornado, the EF5 Smithville, MS storm, and the EF4 Tuscaloosa, AL killer that not only had incredible wind speeds, but tracked for hours. Most tornadoes are generally short-lived. Not this season: The Joplin twister was on the ground for an estimated 7 miles, but rapidly intensified right over a highly populated urban area, moving at a forward speed upwards of 40 mph. Despite the warnings, people died as their dwellings simply disintegrated around them.
Most significant tornadoes form in what is traditionally known as “Tornado Alley”, which encompasses much of the Great Plains and Midwestern states. Recently, a new moniker has been attached to an area that has proven to be just as prone to tornado-producing thunderstorms: “Dixie Alley,” which includes much of the southeastern United States.
What about South Florida’s tornado potential, and are we susceptible to the types of tornadoes that we have seen in recent months inflicting utter devastation on entire communities? The answer is yes, but the likelihood is remote. Since accurate record keeping has been implemented, there has been only a single tornado to affect South Florida with winds even approaching the intensity of the Tuscaloosa/Joplin tornadoes.
Significant South Florida tornadoes: A history
Perhaps the strongest, most violent tornado to ever affect South Florida occurred on April 5, 1925. This was a time when Dade county was largely non-urban, consisting of farmland and the majority of development was confined to the Miami city center and the beaches. But on this date “The Great Miami Tornado” formed near what is now Hialeah and tracked very slowly towards the northeast until the twister eventually entered Biscayne Bay and dissipated. In its wake, five people died and another 35 were hospitalized. Years later, winds were estimated to be in the F3 (old Fujita scale rating of winds between 158-207 mph) damage range based on photographs.
The most recent South Florida tornado fatality occurred on March 27, 2003. In the Brownsville-Liberty City area of Miami-Dade county a man died from flying debris as a strong F2 tornado touched down, heavily damaging 60 homes. This particular tornado tracked for 6 miles, causing an estimated $8 million in property damage.
Perhaps the most famous tornado to hit South Florida occurred on May 12, 1997. Although the damage of this tornado was minor, the storm made international news as it might be the most photographed tornado in history. Your author stood less than 200 yards away from this twister as it spun between the old Miami Arena and the old WTVJ television studios in downtown Miami on its track towards Biscayne Bay where it transitioned from tornado to waterspout, then dissipated.
The majority of South Florida tornadoes are weak, short-lived events that occur in the early spring and summer seasons. The same mechanisms that spawn “super tornadoes” in the Midwest and southeast are simply not in place. Rarely does the jet stream “dig” far enough south to spin up monster tornadoes, particularly by the mid-to-late spring. By the summer, the jet stream retreats far to the north. South Florida also lacks the frequent clashes of warm and cold air masses, which is a key component for the types of tornadoes that we’ve witnessed far too often this year. The chances for a monster tornado to hit South Florida are generally low because of our unique geography. Strong tornadoes can be spawned by hurricanes, and is just another component of the greater threat that a hurricane poses.
Waterspouts are very common along the South Florida coastlines, and the Florida Keys are one of the most active areas for waterspout development anywhere in the world. If a waterspout comes ashore, it is technically classified as a tornado. These can and do cause damage, but they are generally weak and tend to rapidly die out over the land as the spout interacts with friciton from trees, buildings and topography.
History has shown that it is possible for a strong tornado to strike, just like it did on April 5, 1925. History has also revealed that a tornado that could approach the magnitude of the Joplin or Tuscaloosa twister is extremely rare because of geographical and meteorological factors. Tornadoes aren’t as uncommon in South Florida as one would think. For this very reason, any tornado watch or warning issued should be taken seriously. Even a weak tornado – a much more likey event than a “super tornado” – has the potential for damage and, on occasion, death.
To help with tornado disaster relief, please visit: www.redcross.org/SpringStorms