Hurricane Felix Stronger Than Previously Thought

As a bonafide storm junkie, for several months now I have been waiting eagerly for the U.S. National Hurricane Center to release its final reports on 2007's strongest Atlantic hurricanes—Dean and Felix, both Category 5 storms.

These are the best and most comprehensive reports on individual storms produced anywhere in the world, pretty much—providing definitive accounts, based on collating all the available data, on how strong a given storm was, how much damage it caused, and so on.

So imagine my glee when the final report on Hurricane Felix came out last week—and my surprise upon learning that the hurricane center had determined that the storm had been stronger than previously supposed. It now seems that Felix was the strongest known hurricane, globally, in 2007. On September 3, 2007, the National Hurricane Center now estimates that the storm had maximum sustained winds of 150 knots—or more than 170 miles per hour. That's a bump up from a previous estimate of 145 knots (see here). And the 150 knot estimate, says the Hurricane Center, "could be conservative."

Why was Felix upgraded? Some of you may recall that the aircraft reconnaissance flight into the storm at its peak had to be aborted due to extreme turbulence and the pelting of the plane with ice pellets. Well, during that penetration of the storm, the plane carried a relatively new instrument, known as the Stepped Frequency Microwave Radiometer (SFMR). Normally a storm's maximum sustained winds at the surface are estimated based on the wind speeds at the level at which the aircraft is flying (thousands of feet above the sea surface, for safety reasons), but the SFMR allows for measurement of lower level winds.

On that dangerous flight into Felix, the SFMR initially estimated winds of 163 knots in the storm's northeastern eyewall. But at first the hurricane specialists back in Florida thought there must be something wrong with the data. After poring over it again, though, they decided they had to listen to this newish instrument—which helped them to finally conclude that Felix was more powerful than originally supposed.

I happen to be in New Orleans at the moment for the annual meeting of the American Meteorological Society, and today I had the opportunity to discuss this development with Chris Landsea, who is the chief scientific officer of the hurricane center. As Landsea explained, the episode shows that even today, we are getting better at measuring the strength of the strongest hurricanes, thanks to new instrumentation. Landsea doubts that in previous eras, we would have even known that Felix was a Category 5 storm; and he uses the example to argue against the conclusion that global warming is increasing the frequency of the strongest hurricanes.

I don't know about that—we've seen a ton of Category 5 storms lately: 8 in the last 10 years in the Atlantic. Other scientists think this may indicate a true climate trend.

Either way, Felix was an amazing, deadly hurricane—and it still may have been even stronger than we know.