It was going to be a monster storm: Hurricane Irene had just torn through the Bahamas, where it caused over $1 billion in damages, and was moving back out over the open ocean where it was supposed to pick up strength and eventually slam into the U.S. East Coast.
Early predictions put Irene at a possible category 4 storm, one of the most destructive ever, and its path would take it through some of the most densely populated areas of the country, from Washington D.C. up to New York City. In the end forecasters got the track of the storm almost exactly right—Irene came ashore in North Carolina, exactly as predicted and methodically worked its way north toward New England—but the strength of the storm never lived up to the hype. And herein lays the tricky calculations that both hurricane forecasters and political leaders have to make while looking at massive storms sitting off the coast: at what point does a storm look big enough and scary enough to order mandatory evacuations? Mayor Michael Bloomberg in New York City certainly wasn’t taking any chances, shutting down the city’s subway system and ordering mandatory evacuations from some coastal areas; New Jersey Governor Chris Christie also didn’t mess around, evacuating beach communities ahead of Irene. As the storm fizzled, losing its hurricane distinction and becoming a tropical storm by the time it hit Boston, critics were starting to make fun of the “hurricane hype” and questioning the frightening predictions of Irene being one of the biggest hurricanes to ever hit the East Coast. But if you were the mayor of a coastal city would you ever take the chance of repeating New Orleans’ mistake in 2005, ahead of Hurricane Katrina, and not evacuating after dire warnings?
Judith Curry, professor & chair of the School of Earth & Atmospheric Sciences at Georgia Tech Univeristy; president & co-owner of Climate Forecast Applications Network