01 June 2015

It Only Takes One: The Mantra of Inactive Hurricane Seasons

Another post today to usher in the beginning of the 2015 Atlantic hurricane season!  This one is provided by my good friend and guest blogger, Michael Laca.  Michael is a Miami native, and has experienced many hurricanes, both in Miami and on his numerous storm chases over the years.  He is very knowledgeable on hurricanes and particularly hurricane history, and is the owner of the popular TROPMET.COM website that has been around for over 20 years.

His post today address the common phrase It only takes one, referring to the destructive potential of a single landfalling hurricane, regardless of an "active" or "inactive" season. 
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Today marks the beginning of the 2015 Hurricane Season in the Atlantic Basin. With a significant 'El Nino' event currently developing, seasonal forecasts that have recently been released from both CSU and NOAA are suggesting that below-normal tropical cyclone activity can be expected this year. Combined with a nearly decade-long absence of any major hurricane landfalls in the United States, the perceived threat among many coastal residents has been waning.

Of course, as is often heard, 'It only takes one!' to make a season catastrophic, but hearing this has always made me wonder how many times that scenario has actually occurred. Looking back at all "inactive" Atlantic seasons (based on a total of eight, or less, "named" storms within a given season) from 1900-present, how many major hurricanes (maximum sustained winds >= 100kt/115mph) have impacted the U.S.?

As it turns out, it's probably more than you might have imagined. During this period, there were 16 seasons that met my "inactivity" criteria, which also produced a major hurricane impact(s) in the United States. In the map below, the tracks for the 17 major hurricanes (which resulted in a total of 21 separate major U.S. impacts) can be seen, along with their respective peak intensities (in knots), and associated intensity at the time of major impact/landfall. Across these specific 16 seasons, the average number of "named" storms per year was 5.8, well below the statistical average of 9.6. (Note: The statistical average is based on the period 1950-2000, excluding many of the "inactive" seasons on my list, which predate the modern reconnaissance and satellite eras. The statistical average is presented only as a general reference.)


 Some of the most notorious hurricane impacts, and greatest disasters, that this country has experienced have occurred within these "inactive" seasons, including the Galveston Hurricane of 1900, the Texas and Louisiana Hurricanes of 1915, the Okeechobee Hurricane of 1928, the Great Labor Day Hurricane of 1935, Hurricanes Audrey, Donna, Betsy, Beulah, Alicia and, of course, Hurricane Andrew. The combined number of fatalities from these specific storms is a staggering 17,100! Also, looking at the distribution of the U.S. locations impacted by these particular storms, 1 impact occurred in North Carolina, 4 occurred in Louisiana, 6 occurred in Texas, and a whopping 11 major hurricane impacts have occurred in Florida, during "inactive" seasons... 9 of those over the southern portion of the peninsula... and 5 within a 60 mile stretch south of Miami to the middle Florida Keys!

It's important to re-state that this list is strictly limited to impacts from tropical cyclones that were of 'major' hurricane intensity (Category Three, or higher, on the Saffir-Simpson Hurricane Wind Scale). There have been many other impacts in the United States, during "inactive" seasons, from hurricanes (and other storms), below Category Three intensity... some of which have produced devastating results (such as Hurricane Agnes in June, 1972)!

So, regardless of how many tropical cyclones develop in the Atlantic this year, please remember to always be prepared because it truly does ONLY TAKE ONE ... and there have actually been many "ONES" to prove it!

-- Michael Laca

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6 comments:

  1. I guess Super storm Sandy was not strong enough and not enough impact to be mentioned. Wow

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    Replies
    1. Mike,
      Sandy would not be included for three reasons:
      1) it was not a hurricane at the time of its U.S. landfall (it was briefly when it hit Cuba),
      2) even if it was a hurricane when it made U.S. landfall, it would not have been a major hurricane (Category 3+),
      3) there were 19 named storms in 2012, therefore disqualifying it as an inactive season.

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  2. The map needs to be updated. I live in Louisiana and we had some hurricanes in the 2000's. The map say from 1900 to pres.; a little misleading I think.

    ReplyDelete
    Replies
    1. This map is current... which ones do you believe are missing? To be included, the hurricane had to be at least a Category 3 at landfall, and it had to occur during an inactive season.

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  3. What about the impacts of Isabel or her nasty sister Irene? Those were major storms that impacted the east coast!

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    Replies
    1. Hi Mary... neither Isabel nor Irene were major hurricanes when they made landfall on the U.S. Secondly, neither storm occurred during an inactive year.

      As the article states, a major hurricane is a Category 3 or higher, and an inactive season is one with 8 or fewer named storms. Isabel was a Category 2 at its U.S. landfall and there were 16 named storms in 2003. Irene was a Category 1 hurricane at its U.S. landfall and there were 19 named storms in 2011.

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