Warmer Oceans
Scientists say Atlantic Ocean temperatures are warmer now than in the 1970s and 1980s. Hurricane researchers are now certain that water temperature is one of the main contributors to hurricane conditions (the ocean must be at least 80 degrees to sustain a hurricane). Steady winds blowing in the same direction, generally west, and changes in air pressure also work together to nurture a budding hurricane.
     “Some research shows that because the oceans are warmer, this current period of activity could include more major hurricanes,” which could also mean more multi-billion dollar cleanup projects in the wake of the storms, Landsea says.
     Although scientists aren’t certain what causes the decades rise and fall in hurricane activity, specialists are focusing on long-term changes in air pressure patterns and warm and cold ocean currents in the North Atlantic for possible answers.
     Changing air pressure patterns between Iceland and the Azores Islands, several hundred miles off the coast of Portugal, may boost high winds in the Atlantic every two or three decades, says James Elsner, professor of geography and a hurricane specialist at Florida State University.
     The high winds literally blow the top off budding hurricanes and inhibit hurricane activity.
     However, in recent years the tendency toward high winds in the North Atlantic has diminished— one possible explanation for increased hurricane activity, says Elsner.

Even Quiet Years Pose Threat
As scientists point out, however, measuring hurricanes by quantity does not always reflect the amount of damage a hurricane season brings.
     In 1995, meteorologists documented a dramatic increase in big storms with 19 tropical storms, 11 hurricanes and 5 major hurricanes. Even with so much activity, the only major hurricane to hit land was Hurricane Opal, which hit Northwest Florida and Alabama and caused about $3 billion in damage.
     “Just because you have a busy year doesn’t mean a major hurricane will reach land. Sometimes in a quiet year, the one big hurricane comes ashore and is devastating — as Andrew was in 1992,” says Elsner.
     Andrew, the season’s only major hurricane, was the third most-intense hurricane ever recorded, and it required the most expensive storm cleanup in history: $25 billion.

Nasty Wake-Up Call
“Andrew was the wake-up call. Even though it was a quiet year, it reminded people exactly what a hurricane could do,” says Dr. Roger Pielke, a researcher of societal impacts of hurricanes at the National Center for Atmospheric Research in Boulder, Colo.
     A lull in hurricane activity during the 1970s and 1980s led many government officials and the general public to forget about hurricanes, he says. In those two decades the populations of many coastal areas doubled and even tripled as development flourished with little thought of the giant storms.
     In Miami alone, the population jumped 600 percent from 1950 to 1992, he says.
     Pielke estimates the U.S. government spends an average of $5 billion a year on hurricane relief — a high price tag that could be lowered with a few common sense measures, he says.
     From his research on Andrew and other devastating hurricanes, Pielke says better government planning for hurricanes and enforcement of strict building codes are two of the most effective tools society can use to reduce the costs of major storms.
     For example, when Andrew hit Florida the federal, state and local governments had almost no money set aside to cover a major natural disaster and were forced to borrow for the cleanup.
     Officials estimated that close to 20 percent of the cleanup costs could have been avoided if Miami’s storm-conscious building codes had been properly enforced.
     “We need to anticipate hurricane activity. With coastal populations so much bigger now, the costs of above average hurricane activity will only grow,” says Pielke.