RENEE MONTAGNE, HOST:
Meteorologists are predicting the Atlantic hurricane season, which begins today, will be quieter than usual. NOAA's seasonal outlook calls for as many as 11 named storms and up to two major hurricanes. A major hurricane is considered a Category 3 storm or higher. If one hits the U.S., it will be the first time since 2005 - 10 years. That year, there were three - Hurricanes Rita, Wilma and Katrina. NPR's Greg Allen looked back at the busiest hurricane season ever recorded.
GREG ALLEN, BYLINE: How busy? Twenty-eight named storms, 15 of them hurricanes. Four major hurricanes hit the U.S. that year, beginning in July with Hurricane Dennis.
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UNIDENTIFIED REPORTER: The Category 4 storm has maximum sustained winds of 140 miles per hour. Forecasters say it appears likely that Dennis will come ashore somewhere close to Pensacola, Fla. Meteorologist...
ALLEN: Dennis brought a storm surge, tornadoes and lots of rain when it came ashore on Florida's panhandle on July 10. In the U.S., it killed at least three people and caused more than $2.5 billion in damage. And it wasn't even the first hurricane to hit the U.S. that year. Just a few days earlier, Hurricane Cindy made landfall in Louisiana.
RICK KNABB: 2005, no doubt about it, was off the charts, above average activity overall and unusual.
ALLEN: Rick Knabb is the director of the National Hurricane Center in Miami. In 2005, he says, warm water in the Atlantic and low wind shear were just two of the factors that made it such an active season.
KNABB: The conditions were so ripe for such a large chunk of the hurricane season. You just don't see that level of activity every year.
ALLEN: It was a season that used up all of the names designated for hurricanes and tropical storms. For the first time, the National Hurricane Center had to resort to naming storms with letters of the Greek alphabet. And the season continued into 2006. Tropical storm Zeta didn't dissipate until January 7. But for most Americans, the 2005 hurricane season is memorable for one storm in particular - Hurricane Katrina.
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ROBERT SIEGEL, BYLINE: Levees have been breached and officials say residents who remain in the city should get out while there is still a road to safety.
ALLEN: Katrina slammed Louisiana and Mississippi when it came ashore on August 29. It brought a massive storm surge that inundated coastal communities and overwhelmed New Orleans' levees, flood walls and pumps. Over 1,800 people died. Damages were estimated at over $100 billion, making it by far the costliest hurricane ever. It was followed by two other major hurricanes, Rita and Wilma - all formed close to the U.S. coastline. Phil Klotzbach, a meteorologist with Colorado State University, says that helps explain why they did so much damage.
PHIL KLOTZBACH: If a storm forms very far to the east, all it takes is one trough to kind of recurve it out to sea. But if it forms close to the coast, it just has higher odds of making U.S. landfall, so that's one of the reasons why '05 was so devastating was that the storms formed pretty close to the coasts that year.
ALLEN: National Hurricane Center director Rick Knabb says because Katrina formed so close to shore, there was little lead time to warn communities in its path. In part because of the experiences of 2005, the hurricane center has introduced a new five-day tropical weather outlook that tracks weather systems even before they develop into tropical storms and hurricanes.
KNABB: And its most useful when something like Katrina, like Humberto 2007 that formed right off the Texas coast - that product is going to be most useful when the systems are forming right on our doorstep.
ALLEN: Although no major hurricanes have hit the U.S. since 2005, there have been devastating storms. Superstorm Sandy in 2012 and Hurricane Ike in 2008 both brought massive storm surges that caused drowning deaths and were the second and third-costliest storms ever to hit the U.S. Knabb says in hurricanes and tropical storms, 9 out of 10 fatalities come not from wind, but from water. The hurricane center recently has begun issuing experimental storm surge maps, also, storm surge watches and warnings.
KNABB: That, I think, is going to continue to change the game about how we communicate far more clearly than we ever have about the storm surge hazard when the hazard is facing us in real time, about where the storm surge could happen.
ALLEN: This year, meteorologists say with an El Nino in place, it's likely to be a quiet hurricane season. But even if that turns out to be the case, forecasters say people need to be prepared, and they point to 1992. It was a quiet year with just six named storms. But one of them, Hurricane Andrew, devastated South Florida, killing dozens of people and causing more than $26 billion in damage. Greg Allen, NPR News, Miami.