Finding The Bright Side To Pollution: Hurricane Weakener?

Satellite view of Irene in the Northeast
in August, 2011 causing catastrophic flooding.  

Finally! A reason to love air pollution.

Particles in the air from cars and smokestacks and such could sometime weaken hurricanes approaching the U.S. coastline.

Um, Yay?

Oh sure, there's lots to hate about air pollution. It causes illness, lung disease, early death. Plus it's unpleasant.

But according to Dr. Jeff Masters in his Weather Underground blog, air pollution might help weaken hurricanes if they encounter the junk we belch into the air day in and day out.

Citing research published recent in the Journal of Atmosphere Science, Masters said a study look at Hurricane Irene as it approached the North Carolina coast in August, 2011.

Irene had just gone through an eyewall replacement cycle, a common occurence in hurricanes in which the band of intense thunderstorms around the storm's eye reorganized. During the eyewall replacement cycle, a hurricane will usually temporary weaken, then regain strength as the replacement cycle is complete.

This time, Irene did not restrengthen when it finished an eyewall replacement cycle southeast of North Carolina.

Extreme flooding from Hurricane Irene
destroyed this Pittsfield, Vermont house in 2011.   

The research indicates that Irene was encountering air pollution as it approached the United States. The pollution particles reinvigorated and strenthened the outer rainbands of Irene at the expense of its inner core.  

So ultimately, the hurricane came ashore as a category one storm as opposed to the expected and more feared catagory three storm.

Of course, Hurricane Irene continued on, not as a strong hurricane, but one that dumped incredibly heavy rain on much of the Northeast, especially New York and Vermont, causing catastrophic flooding in those two states. 

This is pure speculation on my part, but I wonder if the outer rain bands, strengthened by the pollution, dumped more rain on New York and Vermont than they otherwise would have without the pollution. That combined with the downpours closer to the center of Irene, maybe produced a more prolonged and heavy rainstorm, making the flooding worse.

There is evidence that pollution weakened Hurricane Katrina in 2005 from a monster Catagory 5 storm to a somewhat weaker Catagory 3 storm as it approached the Gulf Coast.

A lot of good that did. New Orleans still drowned.

In his blog, Masters raises an excellent point: If pollution particles weaken hurricanes, why not blast every hurricane that is threatening death and destruction at landfall with particles to weaken it?

Masters reports that this idea is actually a bad one.

It seems the injection of particles must happen at the right time, when the hurricane is going through an eyewall replacement cycle. If you inject the particles at the wrong time, you might actually strengthen the hurricane because the polllution would penetrate to the core of the storm, intensifying the thunderstorms surrounding the hurricane eye.

Most hurricanes don't go through a hurricane replacement cycle at the most convenient time, right before landfall.

There's probably other factors at work, too that would make injecting pollution into hurricanes backfire, making the problems worse.

Still, next time you find yourself choking in the smog, remember, this awful air pollution might be your friend in the unlikely event a hurricane is approaching.

With friends like this, who needs enemies?