Hurricane Isbell sparked one of the most significant tornado outbreaks to strike the Miami metropolitan area on October 14, 1964, including at least nine confirmed tornadoes, four of which were rated significant (F2 or higher) on the Fujita scale. At the time it set a record for tornadoes spawned by an Atlantic hurricane. Although there were no fatalities, 50 people were injured and losses neared $600,000. The most damaging of the tornadoes was an estimated F2 that injured 22 people at a mobile home park in Briny Breezes, causing at least $150,000 in losses. Another F2 tornado shattered a dozen trailers in Eau Gallie, injuring 17 people, with a loss of over $100,000. A few other F2 tornadoes hit the Fort Lauderdale area and in Martin County. Some reports indicated as many as 17 tornadoes, several of which were linked to the same supercell.
Tornadoes hit Florida more often than any other U.S. state, based on rates per , averaging 45–60 annually. Most are of slight potency, size, and duration, with fewer deaths than implied by human population or frequency. Fewer (0.7%) violent (E/F4+) twisters hit Florida than Tornado Alley (2.7%), with strong (E/F2+) or intense (E/F3+) events rare in South Florida. Tropical cyclones only spawn a minority of E/F3+ tornadoes statewide, with their tornadoes mostly forming in front of and to the right of their paths. Most systems that produce Florida tornadoes originate in the Gulf of Mexico. Potent El Niño events tend to favor stronger tornadoes, due to raised levels of wintertime storminess from fronts and cyclones. Deadly tornadoes favor clusters, associating more frequently with "hybrid" and tropical storms than nontropical systems in Florida. Before 1950 many tornadoes, often weak, likely went undetected, due to fewer people living in Florida; many areas, such as the Everglades, remain nearly unpopulated, but with more tornado reports over time due to remote sensors, including Doppler weather radar, and higher population densities.
At 21:00 UTC on October 14, 1964, Hurricane Isbell made landfall near Everglades City as a Category 2 with maximum sustained winds of , having weakened somewhat from its estimated peak intensity of . It crossed South Florida in five and a half hours, moving swiftly at , and entered the Atlantic Ocean in the Juno BeachâÂÂJupiter area. Top winds approached within a compact zone along the southeastern coast. As Isbell headed northeast, a string of tornadoesâÂÂestimates of which ranged from 12 to 17âÂÂformed in its right-front quadrant around the eye, setting a contemporary record for hurricane-spawned tornadoes until Hurricane Beulah three years later. Tornado activity centered mainly on coastal eastern Florida between Eau Gallie and Coral Gables, causing 50 minor injuries, which represented the entire storm total. The tornado series accounted for "a considerable portion" of storm damage in South Florida, according to an official report. At least one tornado family was verified, consisting of serial tornadoes fostered by a single thunderstorm.
An Associated Press dispatch stated that half a dozen tornadoes hit Palm Beach County and three more in Dade County. A tornado reportedly hit Belle Glade, wrecking several trailers and downing trees on U.S. Route 441. Another tornado struck a microwave tower in Loxahatchee. Multiple tornadoes damaged various buildings in Lake Worth. A tornado also caused a trailer collision in Stuart, piling up wreckage. Official records do not show these tornadoes, however.