By Amber Jones, National Science Foundation
Sailors, be forewarned: hurricane science is better than ever, and the prognosis is for rough seas.
Advances in understanding the planet’s ground, water, and atmospheric cycles have vastly improved the ability to forecast the potential for major storms, leading scientists to predict an extremely active hurricane season in 2010. Combining knowledge of the conditions that spawn major storm--based on years of research and observations--with computer modeling, scientists are calling for a 2010 hurricane season so intense that it could approach the record set in 2005.
Some of the recent conditions, partly attributed to a changing climate, have led scientists to call for an increase in the intensity of future seasons for decades to come.
The forecasts, while gloomy, give those likely to be affected--from oil-spill responders currently working in the Gulf of Mexico to insurance companies aiming to protect the bottom line--better tools for preparing and managing the risks.
All indicators point to a 2010 hurricane season “at or beyond” record levels, reports Greg Holland of the National Center for Atmospheric Research (NCAR) in Boulder, Colo., a research facility supported by the National Science Foundation (NSF). To date, the 2005 season, with 28 major storms, according to NOAA records, was the most active on record.
Scientists point to both routine climate variability and global warming as factors contributing to the prognosis for the season that officially began July 1. A hurricane-spawning zone in the North Atlantic, off the west coast of Africa, is experiencing a decade of high ocean temperatures. In May 2010 scientists recorded the warmest sea surface temperatures on record, relegating the previous record from May 2005 to second place.
Other indicators of an intense 2010 season include extra moisture in the atmosphere, a result of the higher sea surface temperatures; lower wind shear, giving hurricanes a greater chance to strengthen; and the retreat of El Niño conditions, which typically inhibit hurricane formation. The retreat could potentially usher in a La Niña, which tends to increase the frequency of hurricanes.
In addition to improved seasonal forecasts, scientists have become much better over the last 20 years at forecasting the tracks of storms, by feeding computer models with a wealth of recorded data on winds, currents, circulation patterns, and interactions with the atmosphere.
Rick Luettich, a marine scientist and director of the Center for the Study of Natural Hazards and Disasters at the University of North Carolina, said this knowledge can help oil-spill responders in the Gulf of Mexico prepare for the coming season. Luettich received a rapid-response grant from NSF to analyze the movement and transport of the oil continuing to spew into the Gulf.
Because hurricanes blow in a counterclockwise direction, water and anything it contains will be swept in a counterclockwise direction. As a storm nears landfall, the rotating winds push water toward the shore on the storm’s right side, and pull it away from shore on the left side. By analyzing data from observations made in previous years, forecasters can model potential surges toward shorelines.
While an accurate surge forecast depends on an accurate storm forecast, Luettich cautioned, the information would be valuable in providing a heads-up about where winds and currents in the Gulf might drive large quantities of oil.
A Katrina-like hurricane, which moved north over the lower Mississippi River delta, could drive oil gathering along the coast west into the marshes east of the delta. In addition, oil would move inland in flooded areas of eastern Louisiana and Mississippi. An Ike-like hurricane path could move oil much farther west along the coast, from the Mississippi River delta to Texas, in addition to being swept inland by flooding.
Both scientists emphasized that managing the risk of such events is a long-term process, requiring investments in science, infrastructure and response capabilities well before they occur. “We have the time and we have the capacity to plan for these” over the next 10-20 years, Holland said. Response to the current season depends largely on infrastructure already in place.
Another sector taking advantage of the improved modeling capability is the insurance industry, particularly reinsurers, which share the risk with individual insurance companies.
“This year’s hurricane forecasts are being taken very seriously by the industry,” said Rowan Douglas, CEO of the Willis Research Network, a branch of Willis Re, one of the world’s largest reinsurance brokers. Douglas emphasized that both industry and society now plan and make decisions in a “modeled” world. He echoed the message that decisions made decades ago to invest in science were essential to developing the current modeling capabilities, which in turn allow the industry to better manage risk and prepare for events such as the pending hurricane season.
Even before Katrina, with losses topping $120 billion, the insurance industry became very interested in hurricane science--prompted by an upturn in major storms starting in the mid-1980s, Douglas said. Hugo, a Category 5 hurricane in 1989 estimated to have caused as much as $10 billion in damage, was “an enormous shock to my industry,” Douglas said. Then came Andrew in 1992, and up to $35 billion in damage. “With Andrew, many insurance companies went bust.”
By the time the most active season in recorded history arrived in 2005, bringing Katrina, Rita, and Wilma, “very few insurance companies failed because modeling prepared us,” Douglas noted. “The ‘modeled world’ worked.”
Models are taken into account in meeting the requirements for insurance companies to be capitalized to withstand the “maximum possible loss.” The Willis Hurricane Index, developed by NCAR in collaboration with the insurance industry, helps identify potential losses so that financial experts can steer capital investments to insurance sectors where they are most needed to manage the risk.
Unfortunately, NCAR’s Holland pointed out, intense storm seasons may become increasingly typical of the future climate. While there remains considerable uncertainty over the long-term frequency of hurricanes, Holland indicated that there is a substantial and growing consensus among scientists that severe--Category 4 and 5--storms could increase by up to 100 percent in coming decades.
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