How Strong Can Tornadoes Get ?

United States Annual Tornado Averages  (Source: NOAA)

Tornadoes are ranked on the Enhanced Fujita Scale that starts with a minimal EF-0 that has winds of 65 – 85 mph.  The strongest tornadoes are ranked an EF-5 and have winds of greater than 200 mph.  Even though wind speeds in an EF-5 tornado are lower than what had been required in an F5 tornado (261+ mph) on the original Fujita Scale, EF-5 tornadoes remain rare. 

All tornadoes, however, are potentially dangerous regardless of intensity.  At least two EF-3 tornadoes occurred late last night in Ohio where extensive damage and a fatality occurred.  Meteorologists are still investigating the damage so the EF-3 ratings are preliminary.  Some of the deadliest and most destructive tornadoes on record have occurred during the month of May. 

2013:  The last EF-5 tornado in the United States occurred on May 20 in Moore, Oklahoma.  It had a long and destructive track as part of a larger, three-day severe weather outbreak.  The strongest tornadoes often develop from something called a “supercell thunderstorm,” which is a long lasting thunderstorm that has a rotating updraft.  

One of the supercell thunderstorms that developed during this outbreak spawned the Moore, OK tornado.  Although not at EF-5 intensity during its entire track, it reached its peak intensity near the town of Moore.  According to NOAA, it caused two dozen fatalities and remains the third costliest tornado on record having caused $2 billion in damage (unadjusted for inflation). 

2011:  The town of Joplin, Missouri experienced a devastating EF-5 tornado on May 22.  According to NOAA, the Joplin EF-5 remains the costliest tornado on record having caused $2.8 billion in damages (unadjusted for inflation).  With a total of 181 fatalities, it was also the single deadliest U.S. tornado since 1947.  The spring of 2011 was an unusually active severe weather season for the United States with a total of six EF-5 tornadoes.  That was the highest annual total since 1974.

1999:  The last observed F5 tornado in the United States before the Fujita Scale was updated or “enhanced” in 2007 occurred on May 3.  The town of Moore, Oklahoma also saw impacts from this devastating tornado that at the time was the third costliest tornado in the United States.  However, the $1 billion in damages it caused (roughly $1.4 billion in 2015 dollars) makes it “only” the sixth costliest tornado in 2019.

1997:  Some might remember the Jarrell, Texas F5 tornado that occurred on May 27.  This was the last F5/EF-5 tornado that developed in the state of Texas and was both destructive and deadly with 27 fatalities.  The Jarrell tornado was unusual since it tracked in a South by Southwest direction, instead of the more common Easter by Northeast direction in North America.