Seasonal Hurricane Predictions Can Only Forecast So Much

MIT Professor Kerry Emanuel describes the limitations of hurricane predictions.


Hurricane Sandy damage via Shutterstock

On August 8—at the cusp of peak hurricane season—the National Oceanic and Atmospheric Administration issued an update to its 2013 hurricane predictions, originally released in May. The good news is that the estimated numbers of named storms, hurricanes, and major hurricanes (think Sandy and Irene) were lowered in the updated outlook. The bad news is that the NOAA’s predictions still call for a 70% chance of an “above-normal season” in terms of hurricane activity, which means that New England may well still suffer at the hands of Mother Nature. MIT professor of meteorology and hurricanes expert Kerry Emanuel, however, says this forecast should be taken with a grain of salt. In fact, he disagrees with the creation of these predictions, entirely.

“I’m actually opposed to the government doing seasonal hurricane forecasts, and let me tell you why I am: the only thing that anyone has ever shown to be somewhat mathematically skilled at is forecasting the number of storms,” he said.

Emanuel offers his reasons why, though predictions like that of the NOAA can be helpful guides, they only offer so much in terms of forecasting what really matters when peak season rolls around.

These predictions don’t exactly have the best track record for accuracy.

In August 1992, Hurricane Andrew became the then-costliest American hurricane, and resulted in 65 fatalities. Up until Andrew’s arrival, Emanuel said, 1992 “was one of the finest years we’ve had in the Atlantic in terms of there being some accuracy in the hurricane forecast.”

“Everybody would’ve been blown away” had they known Andrew was coming. “It was a very, very quiet year.”

The small but mighty Andrew blew away not only meteorologists and the folks at the NOAA, but the homes of people in Louisiana, Florida, and other parts of the southern United States.

Some say we can make inferences about climate change based on an increasingly intense hurricane season, but that may not be the case.

Emanuel, who authored a book called What We Know About Climate Change, says our observations about one season don’t give us much, if any insight.

“One year isn’t nearly enough; it’s almost insignificant. With predicting global climate change, you’d have to look over decades,” he said.

Perhaps most importantly, a hurricane season forecast will never be able to predict what we really want and need to know: risks, damages, loss.

“We’d like to be able to predict any damage that could come from a hurricane, that’s meaningful. Or, how many people it would put at risk—that’s meaningful. But we can’t do that.” Estimates of the number of storms, like the one put out by the NOAA, don’t give a sense of the risk.

Even with ample time to prepare for a rough season ahead, some damage may be inevitable

“The main problem that we have in the United States, if you talk to anybody in my field, is that we have an awful lot of property and people at risk during hurricanes, much more so than any other country. There’s policy that encourages people to build and live in risky places, and not to build particularly well.”

“That’s why people really want to believe the seasonal hurricane forecast,” he said. “They want to see how much potential for risk is out there.” Unfortunately, he says, forecasting doesn’t really provide a great assessment of the risk.