A Brief Comparison of Hurricane Irene to Hurricane Floyd

A Brief Comparison of Hurricane Irene to Hurricane Floyd

Given the similarities of the catastrophic flooding caused by Hurricane Irene this past weekend and Floyd in September 1999, I thought I would prepare this mini-blog on the subject for those interested.

The Paths of Irene and Floyd

As can be seen by comparing the two maps below, both storms originated around the 15° north latitude line although Irene originally developed considerably further to the west of Floyd (about 58° W longitude versus 50° W for Floyd. Floyd’s initial forward motion was slower than that of Irene and Floyd passed well north of the Hispaniola although both storm ended up affecting the Bahamas. Both storms first struck the U.S. mainland in North Carolina although Floyd made landfall about 100 miles further south over the Wilmington area versus Irene’s landfall over the Outer Banks region. Floyd, at its most intense, was a much stronger storm than Irene with a minimum central pressure of 921mb (27.20”) when it was approaching the Bahamas whereas Irene bottomed out at 942mb (27.82”) also in the Bahamas region.





Maximum Wind Speed Comparison Between Irene and Floyd

Floyd, at its, peak was a category 4 hurricane with sustained top winds of 155mph on September 13th, 1999 while just east of the Bahamas. Irene, at its peak, was a category 3 hurricane with 120mph-sustained winds on August 20th, 2011 while passing through the Bahamas. Since Floyd moved slightly further inland than Irene along the East Coast its winds rapidly diminished after making landfall in North Carolina. Below is a table of maximum wind gusts reported for each storm by state:



Maximum Storm Rainfall Comparison Between Irene and Floyd

For both storms it was the flooding rainfall that caused the most damage and fatalities. Below is a table of maximum storm totals by state for both storms:



NOTE: A WU reader is questioning the veracity of the Freehold Township, New Jersey measurement from Irene. If this figure is false, than Irene’s maximum storm rainfall for New Jersey would be 10.20” at Fort Wayne.



NASA has totaled the impressive rainfall from Hurricane Irene using highly precise microwave measurements from a satellite. However, some of these do not jibe with surface observations.



Rainfall storm total map of Floyd based upon surface observations.

Casualties and Damage

It is still too early to know what Irene’s final toll will be so far as deaths and storm damage, but as of this writing there have been 45 confirmed storm-related deaths attributed to Irene. Floyd is credited with 57 deaths and approximately $4.5 billion in damages in 1999 dollars.





Satellite image comparisons of Floyd (top) and Irene (lower) around the time they were making landfall or close to landfall. One can see that Irene had a much larger circulation than Floyd (the two images are not at the same scale—note the U.S. shoreline for comparisons.