LAURA SULLIVAN, host: So Hurricane Irene was just a really bad rainstorm for many of the affected areas. Joe Palca's here from our science desk. And, Joe, why wasn't the damage as severe as predicted?
JOE PALCA: Well, the storm just didn't turn out to be as strong as meteorologists had thought it might be, and that's something that they're aware of. They're very good at predicting the track of storms, and this storm was almost down the line from where they were predicting it was going to go. But they're not as good at predicting the intensity, and the intensity makes a big difference. I mean, this was a Category 1 storm, which has winds of 74 to 95 miles an hour.
And the National Hurricane Center describes those storms as dangerous and will produce some damage. Category 3, which it could've been, some were predicting that it might go up to that, is winds at 111 to 130 miles per hour, and devastating damage will occur. So it's just a question of getting better at predicting the intensity, which the National Hurricane Center is trying to do.
SULLIVAN: How big a role do you think the mass evacuations played in limiting the damage and the human toll?
PALCA: Well, some. You know, a tree that falls on an evacuated city isn't going to hurt anybody, and a tree that falls in a city where there's still a lot of people, more likely. But there are always going to be people who say, well, why did we have to evacuate? when they get home and there's not that much damage. And FEMA administrator Craig Fugate had an answer for that.
CRAIG FUGATE: This is not an easy thing to do. It's not done lightly. But the consequences are too great not to go. And you have to do this based upon forecast often days in advance that you hope doesn't get that bad, but you don't get a second chance.
SULLIVAN: Is there any concern here that people will be less likely to leave in the future when they get this kind of warning?
PALCA: Well, it's always a fine line. I mean, if they're wrong often enough, then, yes, it'll get harder. They have to get it right at least a few times on the nail so that people pay close attention. But since Katrina, people have been pretty aggressive about urging people to evacuate, and it's probably better to err on the side of caution.
SULLIVAN: That's NPR's Joe Palca. Joe, thanks so much.
PALCA: You're welcome.
(SOUNDBITE OF MUSIC) Transcript provided by NPR, Copyright NPR.