In India, they are typhoons; in Australia, they are willy-willies; and in the Americas, they are named after an Amerindian storm god, Huracan. Whatever you call them, hurricanes are some of the most impressive -- and destructive -- forces known.

Katrina and Rita, the two severe hurricanes that battered New Orleans in September, wreaked such havoc that restoring New Orleans to its former condition is not worthwhile, according to two Cornell University faculty members. Speaking at an Oct. 13 public lecture in Phillips Hall that coincided with the American Geological Institute's eighth annual Earth Science Week, the two agreed that the city's future is constrained by sedimentary sinking and the rising of the sea level.

"If you're going to rebuild, build it differently," said Mark Wysocki, senior lecturer in Cornell's Department of Earth and Atmospheric Sciences (EAS). His colleague, Larry Brown, professor and acting co-chair of EAS, agreed.

Focusing on the geological characteristics of New Orleans, Brown noted that the city is particularly susceptible to flooding. New Orleans and the surrounding area, he said, are sinking by an average of 2 millimeters per year, largely due to the copious amounts of silt deposited at the Mississippi Delta.

"You're going to have sinking due simply to the compaction of the sediment under its own weight," Brown explained. In addition, he said, research shows that the sea level is rising at a comparable rate, resulting in a net elevation loss of about 4 millimeters per year.

What will the eventual impact of this be? Displaying a theoretical map of Louisiana in the year 2750, Brown joked that audience members could "start to buy [their] beach front property in Baton Rouge," roughly 80 miles inland from New Orleans. Although such factors as global warming may affect the rate at which these changes occur, Brown stressed that the changes themselves are "fundamentally beyond our control."

Although some data indicate that recent increases in hurricane intensity are related to global warming, Wysocki maintained that drawing any concrete conclusions would require a longer data record than is now available as well as a better understanding of the role of hurricanes in regulating the Earth's heat balance.

He discussed the climatological factors that shape hurricanes, including the conditions required for a tropical storm to form and the different ways they can be classified. Storms are named when their winds reach 39 mph but are not considered hurricanes until the winds reach at least 74 mph. They are then classified, according to such factors as barometric pressure, wind speed and the height of waves in storm surges, into one of five categories, from "minimal damage" Category 1 to "catastrophic" Category 5 storms.

The 2005 hurricane season is unusual: With over a month to go, the record of 21 named storms in a single year has already been tied, and the nation being hit by two Category 5 storms this year -- Katrina and Rita -- has doubled the previous record of one.

Courtney Potts is a student writer intern at the Cornell News Service.