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The Gathering Storm Over How Hurricanes Are Measured

Ever stared down the gaping eye of a category 4 hurricane? It's chilling, even from space.

Ever stared down the gaping eye of a category 4 hurricane? It's chilling, even from space.

Source: NASA

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Call anything a Category 5 storm, disaster or crisis and immediately it sounds awful. The label owes much of its weight to the Saffir-Simpson Hurricane Wind Scale, which is cited routinely (if rarely by its full name) during the Atlantic hurricane season. But a number of destructive storms have underscored the inherent weaknesses in the scale, and efforts continue to try to replace it with something more useful.

It’s a five-step scale created in the 1970s by Herb Saffir, an engineer, and Bob Simpson, a meteorologist, to categorize a hurricane’s power, from Category 1 (sustained winds of at least 74 miles per hour, or 119 kilometers per hour) to Category 5 (157 mph and greater). Anything above a Category 3, which is reached when a storm’s winds hit 111 mph, is considered a major hurricane. The scale is used primarily in the Western Hemisphere, where the U.S. National Hurricane Center has responsibility for forecasting.