There are three massive differences between Sandy and Irene.

1) Irene basically collapsed and weakened right before landfall. Sandy by all accounts getting stronger. She will pass over the Gulfstream where waters are much warmer than they are now. Keep in mind Irene did $15B in damage

2) The trajectory. Irene came in from the due South. This will be coming from east to west. There is no historical basis to evaluate Sandy on, because there really has never been a storm this size come from the East this far north. Nobody knows what impact is going to be say in the LI Sound with the surge

3) Trees. Right now the leaves on the trees are basically dead. The weight of the rain fall will cause branhes to collapse causing massive power outages of hundreds of miles. With temps in a lot of the Northeast dropping into the 30s each night now, that is going to be a big problem

Here is the best satellite on Sandy. You can see how huge and how it appears to be getting more organized. The trip over the Gulf Stream will be interesting.

http://rammb.cira.colostate.edu/temp..._to_display=50