Tornado in a Hurricane Strength

[Scott Nelson]

First off, I apologize that this question is not under the tropical weather threads. But since my interest is Tornado specific... placing it here seemed a better fit overall.

Knowing that hurricanes drop there fair share of Tornadoes, I was wondering what the most destructive Tornado associated with a Hurricane has been to date? Thinking that the combined effects of both systems would make it a bit more difficult to F scale it accurately. Also wondering if a weaker hurricane might be more prone to a weaker tornado. Or does the Cat strength have little bearing?

 

[IAN GIAMMANCO]

Often dry air entrainment contributes to tornadic activity associated with a landfalling tropical cyclone, Ivan is a pretty decent example, some of which were damaging tornadoes in the Panama City area. Also typically most tornadoes are found in the more cellular convective elements in outer rainbands where mean winds associated with the tropical cyclone circulation are lower, making damage doc. a little easier. I remember from Andrew in south LA there was I believe an F2 which impacted LaPlace (i'm sure its not the strongest), also I believe Gilbert spawned a pretty substantial wedge tornado over south texas in one of the outer convective bands. As for the strongest, maybe someone else can take a stab at that...

 

[Howard Robinson]

Scott, from everything I have been told about tornadogenesis in hurricanes is that most tornados that are spawned, are weak (ie F0 to F1). As to the strongest, I can look around and see what I can find. I heard about a possible F3 in Andrew, but I can't find anything about it.

 

[Jason Harris]

Claim here of F4 during hurricane Carla
http://www.wxresearch.org/newsletter/Mar99.html
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Another example of an F4 tornado nearby was during Hurricane Carla in Galveston County on September 12, 1961.
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Another claim of F3/F4 during hurricane:
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Although F3 and F4 tornadoes have occurred with landfalling TCs (Grazulis 1993, Vescio et al. 1996), none were found in exiting systems.
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Here are the sources from the citations:

Grazulis, T.P., 1993: Significant Tornadoes: 1680-1991. Environmental Films, St Johnsbury VT, 1326 pp.

Vescio, M.D., S.J. Weiss, and F.P. Ostby, 1995: Tornadoes associated with Tropical Storm Beryl. Preprints, 21st Conf. Hurricanes and Tropical Meteor., Amer. Meteor. Soc., Miami, 469-471.



Apparently no record of F3 or higher with exiting hurricane:

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Violent (F4, F5) and F3 tornadoes have not been observed with exiting TCs. Given the inherent interpretative subjectivity of the F-scale (Doswell and Burgess 1988), however, the possibility of such tornadoes producing F3 or greater damage cannot be disregarded. Storm-relative azimuthal mapping of both tornado locations and their F-scale is planned, analogous to the motion-relative F-scale sums plotted by McCaul (1991). In addition to most-intense spot damage -- the basis for each F-scale rating -- numbers and areal coverage of tornadoes are factors in the public tornado hazard and in the SPC forecast decision process. For this reason, comparative analysis of total tornado event threat associated with exiting TCs may be performed using the Destruction Potential Index (Thompson and Vescio, 1998). Such an analysis could be extended to a much broader spectrum of TC tornado events in a separate study.
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http://www.spc.noaa.gov/publications/edwards/exittors.htm

 

[Rob Sermon]

Scott, after hurricane Katrina , Gustav, and Ike, I flew many SAR, and photo recon missions with the Civil Air Patrol. Although F3/F4 damage could be seen, the only thing I could see from the air was a very intricate scrolling in the sugar cane fields.

Tornados, absolutely, F0/F1. Sugar cane is a grass, but like corn or bamboo, it is rather sturdy.

The area around the structural damage bore no signs of tornadic activity. The only thing I could figure is straight line, or down burst winds.

 

[Kevin Stumpf]

Atlanta International Raceway was hit by an F-2 by the remnants of TS Cindy in 2005. About the same time that was going on, I was taking off from Atlanta Airport. The downdrafts we encountered were pretty bad as we banked south in the Hampton Ga area. We had been on ground hold for almost 2 hours while the core of the system passed over the airport. I thought we were going to crash. Every 15 seconds the plane would drop. When it wasn't dropping it was shaking so bad the lights and tv screens were flashing of and on. Rain or hail was so heavy I couldn't see the wing outside my window.

 

[Perry Williams]

First off, I apologize that this question is not under the tropical weather threads. But since my interest is Tornado specific... placing it here seemed a better fit overall.

Knowing that hurricanes drop there fair share of Tornadoes, I was wondering what the most destructive Tornado associated with a Hurricane has been to date? Thinking that the combined effects of both systems would make it a bit more difficult to F scale it accurately. Also wondering if a weaker hurricane might be more prone to a weaker tornado. Or does the Cat strength have little bearing?

To my knowledge, there have been two tornadoes associated with landfalling hurricanes since 1950 which are rated as F4...

Galveston, Texas in September 1961 (hurricane Carla)
Larose, Louisiana in October 1964 (hurricane Hilda)....this one killed 22 people

Please bear in mind, both these tornadoes were rated years after they occurred (the Fujita scale was developed by Dr Ted Fujita and Dr Allen Pearson in the early 1970's).