Just weeks after Hurricane Katrina savaged the Gulf Coast, another monster, Hurricane Rita, is heading there. Several hurricanes pounded Florida last year. That has plenty of people wondering what's going on: Are hurricanes getting stronger and more frequent?
"We're now in a very active hurricane era," confirms Dr. Gerry Bell, a seasonal hurricane forecaster for the National Oceanic and Atmospheric Administration (NOAA). "Last year was very active, the year before that was very active. …This active hurricane era began in 1995. Since 1995, nine out of the last 11 hurricanes seasons have above normal."
Bell tells Russ Mitchell of The Saturday Early Show hurricane activity comes in cycles that can last several decades.
It seems, Mitchell observes, 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."
"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."
There are other factors as well, such as warm water, which hurricanes feed off.
Sea surface temperatures have risen, Pinkston notes, 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."