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Subject : L7) What is the largest known outbreak of TC tornadoes?
Contributed by Bill McCaul, Chris Vaccaro and the National
Hurricane Center
2004's Hurricane Ivan caused a multi-day outbreak of 127 tornadoes, with
the bulk of the tornadoes on 17 September in the mid-Atlantic region, some
two days after Ivan's landfall in Alabama. State-by-state tornado counts
from Ivan include Florida with 22, Georgia 25, Alabama 8, South Carolina
7, North Carolina 4, Virginia 40, West Virginia 3, Maryland 9, and
Pennsylvania 9. There were 26 tornadoes on 15 September, 32 on 16
September, 63 on 17 September, 2 on 18 September, and 4 on 19 September.
At least 7 people were killed and 17 injured by these tornadoes.
The previous record was during Hurricane Beulah, which spawned a reported
115 tornadoes in southeast Texas during the first several days after its
landfall in September 1967 (Orton 1970).
Frances of 2004 is close behind in third place, with 106 tornadoes, and
Rita of 2005 is in fourth place with 92. For a list of the top 25 tornado
producing TCs, see the website:
http://www.tornadoproject.com/alltorns/tcyclone2.htm
While it is difficult to predict which TCs will produce large tornado
outbreaks, there is evidence suggesting that the likelihood of a major
outbreak increases for TCs that are large, intense, are recurving and
entering the westerlies, have forward speeds from about 8-18 mph, and are
interacting with old, weakened frontal boundaries. In addition, the TC's
right-front quadrant must receive significant exposure to land, and this
strongly favors TCs making landfall on the Gulf coast as opposed to those
grazing the Carolinas (McCaul, 1991; McCaul et al.,
2004).
Last updated October 4, 2006
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