In a 2003 paper about the household costs of hurricane evacuation I wrote in the concluding paragraph:
This research should be increasingly important in light of the largest peacetime evacuation in United States history during Hurricane Floyd [Pasch, et al. 1999] and predictions of increases in the number of land falling major hurricanes [Gray, et al. 2000].
It turns out that both claims are somewhat bogus. The Hurricane Floyd evacuation involved a lot of people but no one really knows if it was the largest peacetime evacuation. Al Gore has been credited with this little bit of deceipt.
And today the WSJ's Numbers Guy takes a look at seasonal hurricane forecasts (In Hurricane Forecasting, Science Is Far From Exact) and finds that they are somewhat bogus:
In recent weeks, CNN, MSNBC and CBS -- and dozens of newspapers around the country -- all reported forecasts by Colorado State professor William Gray, the pioneer of long-range hurricane predicting, of eight hurricanes this year (revised up from seven in April). Other forecasts from the National Oceanic and Atmospheric Administration, Florida State University and University College London project between six and eight hurricanes.
But my examination of forecasters' records over the past six years -- the period in which all four groups have been publicizing their predictions before the hurricane season begins -- shows that none do much better than a simple five-year average, a number that can be derived without expertise in climatology or statistics (more on this in a moment) ...
... It turns out that all four forecasts have missed by between 1.3 and 1.5 hurricanes each year. But a more simplistic method, a five-year moving average of hurricane counts, does just as well, missing by an average of 1.4 hurricanes each year. (To arrive at a five-year moving average, you simply add the counts for the previous five years and divide by five. For instance, to get a prediction for the number of hurricanes in 2000, I averaged the actual counts from 1995 through 1999. For 2001, I used counts from 1996 through 2000. I did this for each of the six years I evaluated.)
So, the complicated climatic forecast methodology might not be better than a simple model based on past history (as is often the case with macroeconomic forecasts). Either way, hurricane activity seems to be increasing.
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