Washington, D.C. ? Watching for changes in the inner eyewall of a hurricane may help forecasters overcome one of their most perplexing challenges: predicting sudden strengthening or weakening.

A research team led by Robert A. Houze Jr., a University of Washington professor of atmospheric science, is reporting evidence that clouds around the eyewall of a storm can cause sudden changes in intensity.

The findings, in today’s issue of the journal Science, are based on analyses of data collected in 2005 in Hurricanes Katrina and Rita.

The strongest winds in a hurricane circulate in the cloud wall that surrounds the relatively calm and clear eye of the storm.

Taking measurements from aircraft flying into the storms, the researchers led by Houze found that a “moat” of clear air sometimes forms outside the eyewall. Winds funneling toward the center of the storm will then form a new eyewall outside the original one, cutting off the storm center from the incoming flow of energy and eliminating the old eyewall.

Using aircraft to study these changes could help improve forecasts of storm intensity, Houze said.