Hurricane Season Only Half Over

October Called The Busiest Storm Month In South Florida

(CBS)  The midpoint of the fourth-busiest hurricane season on record has just passed, but America's coastal areas aren't out of the woods yet.

In South Florida, reports CBS News hurricane analyst Bryan Norcross, October is traditionally the busiest hurricane month. That's generally when storms form close to the United States., much the way Katrina and Rita did.

"The storms that have formed this year have tended to form close to the United States, Norcorss said in an interview with co-anchor Russ Mitchell on The Saturday Early Show. " Think about Katrina and Rita. They didn't form way out in the ocean as we saw last year."

Rita is the 17th named storm of the Atlantic hurricane season, which began June 1 and continues through November. That has plenty of people wondering what's going on: Are hurricanes getting stronger and more frequent?

"Well, I refer them back to the late '40s, where we had five major hurricanes in six years," Norcross says. "In the late '20s, we had a mega-hurricane called the Great Miami Hurricane, in 1926. Up the coast, Palm Beach was wiped out and maybe 3,000 people died in the great 1928 hurricane. So it has happened in the past.

"Also, there was a year, Russ, 1893, when over 2,000 people were killed in South Carolina, 2,000 people were killed in Louisiana. A hurricane hit New York City all in the same year. So the hurricane events have happened, but the changes in media have made our perception of it different."

The changes in media, and in forecasting, also has cut the casualty rates over the decades. Early warning has enabled cities and towns to evacuate, moving their citizens out of harm's way.

More than a week ago, Gerry Bell, a seasonal hurricane forecaster for the National Oceanic and Atmospheric Administration (NOAA)., told Mitchell that hurricane activity comes in cycles that can last several decades.

It seems, Mitchell observed, Mother Nature has mood swings.

"The previous active hurricane era was during the 1950s and 60s. Then we were pretty inactive for about a 25-year period, from 1970 to 1994, and now we're back in an active hurricane era," Bell points out.

In the '50s and '60s, the Gulf Coast was hit hard and often, as storms such as Audrey, Donna, Betsy and Camille came ashore. In the '70s and '80s, that same region had only one major hurricane, Frederic, which hit Mobile, Ala. in 1979.

But since 1990, the number of big hurricanes in the Gulf region is up again and, says Bell, there's no end in sight: "We can expect continued high levels of hurricane activities and high levels of hurricane landfalls for the next decade, or perhaps even longer."

Why? Bell says hurricane cycles are primarily driven by rainfall patterns in Africa and the Amazon basin.

"Those rainfall patterns tend to last for 20 to 30 years at a time," he explains, "and as a result, so do the wind and air pressure patterns over the Atlantic that control hurricane activity."

Sea surface temperatures have risen, Mitchell noted, but scientists point out that ocean temperatures go through cycles as well, and that we're in a warm cycle.

Still, many in the field believe global warming may be at least a contributing factor in increased water temperatures.

"The water temperature is quite essential to the strength of a hurricane, and it only takes 2 to 4 degrees Fahrenheit to be the difference, to being able to support a Category 3 hurricane and a Category 5 hurricane," says Michael Schlacter, a meteorologist with Weather 2000. "So (whether) it's global warming, the cycles, or just a hot summer, those little bits of increase in temperature can mean a big difference in how severe the storms are."

How concerned should people be who live in an area that's susceptible to hurricanes?

"I would be very concerned," Schlacter warns. "As far as Americans love being near the beach, and as far as we have severe weather that's constantly threatening these coastlines, it's kind of a teeter-totter that we're going to be living with for some time."