Down Year for Hurricanes, Tornadoes

I re-tweeted this article from the Examiner regarding the slow tornado and hurricane season.  To be honest, I wasn’t convinced of everything in the article, so I decided to do a little of my own research.  Turns out they were pretty much spot on.

Click for larger image.

The above graph from the Storm Prediction Center shows the current tornado total in the 10th percentile, or even slightly lower.  You can see the total was running around normal until later summer when the number of tornadoes nearly flat-lined.  Some of this can be attributed to the lack of land-falling tropical cyclones.  Hurricanes and tropical storms often spawn tornadoes in their outer rainbands and this contributes to the Fall tornado total.  Another common source of tornadoes in the Fall are intense mid-latitude cyclones.  We saw these on a couple occasions in October, but the warm sector of the storm was not conducive to supercell development.

On a very positive note, deaths related to tornadoes are down significantly this year compared to years prior.  The previous three years averaged 91 fatalities per year from tornadoes, but only 22 deaths have occurred so far this year.  It’s easy to say this decrease is due to fewer tornadoes, but 2006 and 2007 saw similar down years to this point.

Click for larger image.

In all likelihood, the decline in fatalities is due to a bit of luck.  The tornadoes that have formed this year probably haven’t hit as many (or as heavily) populated areas compared to the previous years.  This is, of course, a good thing, but it’s not something anyone can control.  Something to be thankful for next week, to be sure.

The lack of Atlantic hurricane activity has been well-document in this corner of the internet.  Even with a relatively active Pacific, the global tropical activity is still well-below normal and rivaling the lowest in 30 years.

Click for larger image.

We’ve shown similar images for Accumulated Cyclone Energy in previous posts.  Ryan Maue at Florida St. continues to provide excellent information on this subject.  Of course, many will point to the El Nino as the reason for the quiet Atlantic, but the keen observer will note the high ACE totals in 1997-98 during one of the strongest El Nino events in recorded history.  Clearly something else is at work here, particularly on a global scale.

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