Lightning Helps Predict Hurricane Fury

Jan. 15, 2009 -- In 2006, cyclone Nargis roared ashore in Myanmar in the Indian Ocean, devastating coastal communities and claiming an estimated 130,000 lives.

Initially packing winds of 90 miles per hour, Nargis caught forecasters by surprise when it suddenly intensified until winds reached 130 miles per hour just hours before landfall on May 2. New research is suggesting forecasters could have seen the danger coming, if only they had been watching the storm's lightning patterns carefully.

For the world's most powerful storms, hurricanes have surprisingly little lightning at their core. That's mainly because winds within 60 miles from the eye are horizontal, which prevents the huge updrafts necessary to form ice crystals and supercooled water that usually lead to lightning.

Related Content:

But Natalia Solorzano of Bard High School Early College in New York and a team of researchers found that with Nargis, large spikes in lightning activity occurred near the eye wall 36 hours before its deadly intensification. They attribute the increased lightning to a phenomenon known as "eyewall replacement," one of the many ways hurricanes intensify.

"Hurricanes are made of concentric rain bands," Solorzano said. "The eyewall is the innermost band. In changes in intensification it gets replaced by another band" from further out in the storm. The outer band usually has more updrafting associated with it, and more lightning activity.

As the outer band migrates inward, it causes large updrafts in the storm's core, which further increase the frequency of lightning strikes. But replacement can also signal weakening in the storm, and forecasters have to pay attention to all of the weather conditions surrounding the storm to predict how it will behave.

"You can't look only at lightning," Solorzano said. "But lightning helps you see that a storm is probably going to intensify, given that other conditions in the atmosphere are right for it."