The Weather Notebook: Lightning Pollution

Lightning Pollution
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The old saying goes, that lightning never strikes the same place twice. Tell that to the people of Houston, Texas. Lightning strikes that city an astonishing 1,700 times per month.

Hi, I'm Brian Yeaton and this is the Weather Notebook.

As part of a class project, Professor Richard Orville of Texas A and M University had his meteorology students count the lightning strikes over various southern cities.

Orville: There's tends to be a concentration of lightning over the Houston area. And if we look at that in detail we find twice as much lightning over Houston as in the surrounding area.

That's not surprising, says Orville, because heat generated by large, densely populated urban areas causes the updrafts needed to create thunderstorms. But then one student noticed that the rural city of Lake Charles, Louisiana was hit by lightning nearly as often as Houston and the hunt was on for an answer.

Orville: Lake Charles's population is 70, 80,000 people. You got 4 million in Houston. So population is not going to explain the enhancement here.

Along with heat, moisture is an important ingredient in a thunderstorm recipe. Houston is near the Gulf of Mexico - a source of moisture. But Lake Charles is much further inland.

Professor Orville noticed that Houston has nearly 50% of the nation's petroleum refining capacity. And in Lake Charles.

Orville: There are refineries. I have driven along route ten and for a mile or so, two miles. There's nothing but refineries.

Orville now believes that air pollution links the two cities and their high lightning levels. He thinks that particulates in the air pollution from the refineries rise into the atmosphere, where they are the right size to attract moisture and eventually form storm clouds.

So far, it's still just a theory but Orville plans to soon take to the sky in a research plane, fly over the oil refineries and learn just what those Texas clouds there are really made of.

Thanks today to writer George Homsy of Canandaigua, New York. The Weather Notebook is a production of the Mt. Washington Observatory and is supported generously by Subaru of America.