Since 1988, the U.S. has been hit by a near-Biblical string of weather disasters, causing a staggering $93 billion in damage (table). By comparison, bad weather caused only $5 billion in damage the preceding five years (1983 to 1987), according to figures from the National Climatic Data Center in Asheville, N.C.
Why the sudden surge of weather-related damage? Bad luck, in part. But the U.S. has also become more vulnerable to severe weather. Exposed coasts and flood plains now are filled with homes and businesses. And many meteorologists suspect there's more variability because of the greenhouse effect and other climatic changes.
But the bill from bad weather could have been even bigger if forecasting hadn't improved. "Our five-day forecast now is as good as our three-day forecast was 8 to 10 years ago," says James Howcroft, deputy director of the National Meteorological Center at the National Weather Service (NWS) in Camp Springs, Md. The NWS is in the middle of a 15-year, $4 billion modernization program that should further boost its forecasting ability. New radar systems already are being used to give earlier tornado warnings in Oklahoma and Florida, saving lives and property.
Soon, forecasts of temperature and rainfall a season or more in advance may help prevent more damage. "You can save lives with short-term forecasts," says Richard Anthes, president of the University Corporation for Atmospheric Research in Boulder, Colo., "but long-term outlooks are much more valuable in terms of agricultural strategies, water-resource management, and industry."
With a few months' warning of a drought or flood, farmers could switch crops and planting times to take advantage of conditions that are wetter or drier than usual. And "if you had a longer outlook, you might manage your dams and reservoirs differently," says John A. Dutton, dean of the College of Earth & Mineral Sciences at Pennsylvania State University. If the Midwest floods had been anticipated, the U.S. Army Corps of Engineers could have let water out of reservoirs in advance to make more room for heavy rains.
Up to now, the NWS has made 90-day forecasts using methods that don't predict rainfall very well. But there are promising new forecasting techniques based on the El Ni o effect, which links Pacific Ocean temperatures to climate patterns around the world, says NWS meteorologist Ants Leetmaa. Soon, the NWS will start releasing experimental long-run forecasts of U.S. temperature and precipitation using the new model. "We're going to be able to do better than we're doing now," says Leetmaa. If he's right, it could help the U.S. avoid getting soaked in the future.