Hurricane Season 2017 will be remembered for the storm that wouldn’t stop raining and the number of Category 5 hurricanes within a short period of time. We have been hearing from climate change “experts” that the storms would become more violent and numerous. But has this happen? Will 2017 be the beginning of something new or just par for the course? Could it be that perhaps we are just in a cycle? All weather has patterns, cycles they follow.
So let’s look at few data points to begin this conversation. For the purpose of this post, we are going to look at hurricane intensity based on barometric pressure. While there are many data points we can use, I want to start with this information.
The Weather Channel has ranked the strongest hurricanes based on lowest barometric pressure achieved during the lifetime of the storm.
|Storm Name||Pressure in millibars|
|1924 Hurricane/ 2004 Ivan||910|
|2007 Dean / 1998 Mitch||905|
|1935 Labor Day Key West||892|
The National Hurricane Center (NHC) ranked the strongest hurricanes based on lowest barometric pressure at landfall.
|Storm Name||Pressure in millibars|
|1926 Miami / 1960 Donna||930|
|1928 Lake Okeechobee||929|
|1935 Labor Day||892|
What makes both of these charts significant is the data used to describe the strength of the storms. The Weather Channel chose to use the lifetime lowest barometric pressure reading while The National Hurricane Center chose to use the barometric pressure reading at landfall. What difference does that make and why would we care? Different measurements provide different results. Between the two charts only three hurricanes show on both charts. Depending on what information is being used, the results provided will give completely different information. It can also appear that one is better than the other. This is where wording is vital. Is it the strongest hurricane based on pressure at any time during the storm (Wilma in 2005) or is it the strongest hurricane when it comes ashore (1935 Labor Day Key West hurricane)? That provides two completely separate answers that are 70 years apart! It’s not misleading but it is manipulation of the data.
So that begs the title question? Are hurricanes becoming stronger? In 2016, Hurricane Matthew was the first category 5 hurricane in the Atlantic since 2007; nine years since a major hurricane had appeared in the Atlantic. So if storms were becoming frequent and dangerous, wouldn’t there have been a storm between that time? Hurricane Matthew reached a minimum pressure of 934 millibars, not even making the Top Ten on either lists. Hurricane Dean in 2007 which makes The Weather Channel’s list, was the first Category 5 to have a landfall since Hurricane Andrew in 1992. So it appears that storms are not intensifying and hitting land very often. In fact, looking at the stats from the National Hurricane Center, only 27 Category 4 or higher storms have hit the United States mainland since 1851. So in 166 years, only 27 Category 4 or 5 storms have hit but yet, we are being told that the storms are becoming more frequent. Does this make sense? When you read that only 27 Category 4 or 5 storms have hit the mainland since 1851, does it make sense that the storms are becoming stronger and more frequent? Don’t look at what the “experts” say but look at that fact. Approximately every 6 years, a Category 4 or 5 storm will hit the United States mainland. That would be a cycle or a pattern, right? And does that mean that every 6 years, we have a Category 4 or 5 coming onshore? No, it means on average that is what happens.
Here’s what I would like us to think about. What sells ratings? Sensationalism, right? So, the more something seems to be unbelievable the more likely people will tune in, right? Maybe this has happened with our weather media now too. I am not absolutely sure but it seems possible. Don’t you want to tune in to see where Jim Cantore will pop up next? I know I do! And if he is heading to my town, I know it’s going to be a bad weather day. Please do not get me wrong, Hurricane Harvey, Irma and Maria were intense and destructive. I myself was personally affected by Hurricane Irma, and know people that are still recovering from all of them even here in October 2017, months later. I have friends and family that lived to tell tales of what they experienced this year. But would it have made the media if they were Category 1 storms that just brought a little rain? Or if it stayed out in the ocean for fish food? We will talk about Hurricane Jose because he was all confused and wandered around for a week trying to figure out what to do. And that brings up another topic which I want to defer to another post – the science behind storms. Why they form and why they take the paths they do? What influences intensity, size and movement? There is science still used to predict and determine the tracks.
So back to the question on this post… Are storms, in this post specifically Atlantic basin hurricanes, becoming worse? I think it is a matter of the data reviewed and how it is measured.
Eric S. Blake, Christopher W. Landsea, and Ethan J. Gibney – NWS NHC 6 (PDF): The Deadliest, Costliest, and Most Intense United States Tropical Cyclones From 1851 to 2010 (and other Frequently Requested Hurricane Facts) – Updated August, 2011. <http://www.nhc.noaa.gov/data/publications.php>
Chris Dolce and Jonathan Erdman – For First Time Since 2005, Four Hurricanes Make U.S. Landfalls in One Season Posted Oct 8 2017 08:15 AM EDT <https://weather.com/storms/hurricane/news/2017-10-07-four-us-hurricane-landfalls-nate-maria-irma-harvey>
Nick Wiltgen – Strongest Hurricanes: 10 Most Intense Atlantic Hurricanes on Record posted Apr 7 2014 06:45 PM EDT <https://weather.com/storms/hurricane/news/strongest-hurricanes-most-intense-atlantic-hurricanes-20130911#/1>