No other country in the world has more tornadoes than the United States. On average, over 1,000 tornadoes are reported in the United States every year, resulting in 68 deaths and over 1,500 injuries. South Florida is certainly no stranger to tornadoes and severe thunderstorms, and they occur more frequently here than some people realize. Since 1992, South Florida has averaged 10 reported tornadoes per year, and since 1950 a total of 155 tornadoes of EF-1 or EF-2 intensity on the Enhanced Fujita Scale (winds greater than 85 mph) have occurred. South Florida tornadoes occur with a variety of weather systems including: strong winter/spring cold fronts, waterspouts moving onshore, tornadoes embedded in the outer rain bands of tropical storms and hurricanes, and even from ordinary afternoon thunderstorms if the conditions are just right.
Over 90% of South Florida tornadoes fall in the EF-0 and EF-1 category, which translates to winds less than 110 mph. Impacts from these tornadoes typically include: significant damage to mobile homes, uprooted trees/broken tree branches, downed power lines, minor structural/roof damage to buildings, and patio/pool screen enclosures. A total of two tornadoes were reported in South Florida in 2021, and only 12 in the past three years combined. This reflects the year-to-year variability in tornadoes, and not necessarily an indication that tornado activity will continue to decrease every year. On Jan. 16 of this year, two tornadoes struck parts of Collier County, equaling 2021’s total in only one day. A relatively inactive year can be followed by an active year. Since 2015, seven people in South Florida have been injured by tornadoes, a sign that ANY tornado is dangerous.
Even waterspouts (tornadic circulation on water) can be dangerous to boaters as well as to those at the beach. On May 25, 2015, a waterspout moved onshore Fort Lauderdale Beach and flipped a bounce house in the air about 30 feet, injuring four children who were in the bounce house at the time. More recently, on Aug. 19, 2020, a waterspout moved along the beach at Golden Beach, damaging fences and trees along a narrow path near the shoreline.
As was the case last month, tornadoes can occur in the winter, but occur mostly from May to August when thunderstorms are most frequent. Most South Florida tornadoes are relatively small and short-lived. This means that it is often very difficult to give plenty of advance warning. In many cases, only a few minutes of warning are given between the time a warning is issued by the National Weather Service and the tornado touchdown. Nevertheless, even a few minutes of warning can make the difference between life and death.
Knowing how to receive weather warnings is critical to your safety. Fortunately, there are many ways to get these warnings. One option is owning a NOAA Weather Radio.
Having a NOAA Weather Radio is a critical component of the warning system. In fact, having a weather radio available to alert of an approaching tornado has proven to save lives, especially for nighttime tornadoes when people are normally asleep and otherwise wouldn’t receive alerts. Local media will also relay tornado warnings via the Emergency Alert System (EAS).
In South Florida, there are six different transmitters relaying weather information 24/7 (Figures 3 and 4). Weather messages are repeated every four to six minutes and are routinely updated every one to three hours, or more frequently when severe weather strikes. During severe weather such as tornadoes, NWS forecasters can interrupt the routine weather broadcasts and insert special warning messages concerning imminent threats to life and property. The forecaster can also add special codes to warnings that trigger “alerting” features of specially equipped receivers. In the simplest case, this signal activates audible or visual alarms, indicating that an emergency condition exists within the radio listening area and alerts the listener to press a button or turn up the volume and stay tuned for more information.
There are also many mobile services available to alert of tornadoes, including Wireless Emergency Alerts (WEA) which allows people who own wireless smartphones and other enabled mobile devices to receive geographically-targeted, text-like messages alerting them of imminent threats to safety in their immediate area. Apps such as the one from FEMA provide free weather alert notification to mobile devices.
It is important to understand the meaning of the terminology meteorologists use to assess the threat of tornadoes in your community. A Tornado Watch means that atmospheric conditions are conducive for tornadoes. Remain alert for approaching storms. A Tornado Warning means that a tornado has been sighted by a weather spotter or member of the public, or indicated by weather radar.
Severe thunderstorms are also fairly common in South Florida. These are defined as thunderstorms containing wind speeds of at least 58 mph and/or large hail of at least one inch in diameter. Severe thunderstorms can occur year-round but are most common from March to August. Winds in excess of 58 mph can cause damage to trees, cause signs to fly through the air, knock down power lines, and even cause structural damage to buildings. Large hail, although usually not damaging in South Florida, can still pose a threat, especially in urban areas where vehicles can suffer damage. Large hail can also damage crops.
Tornado and severe thunderstorm warnings are normally issued within 30 minutes of an expected impact, and people are urged to take immediate protective action due to the imminent nature of the threat.
IMPORTANT TORNADO SAFETY TIP
When a tornado warning is issued for your area, move immediately to your pre-designated place of safety, which should be an interior room or hallway on the lowest floor away from windows or underneath a desk or table if a windowless room is not available. In a multi-story building, go to the lowest floor.
For more information on tornadoes and thunderstorms, including safety information, visit the National Weather Service Tornado website and the National Weather Service Severe Thunderstorm website.
Make sure to visit our website at weather.gov/miami for the latest weather information, including information on potential tornado and thunderstorm threats, watches and warnings. Also monitor NOAA Weather Radio and local media, particularly during potentially threatening weather days.