Very simply put. Bloomberg hyped Irene because he believes in the now falsified AGW premise. So he ordered the evacuation of New York, when it should not have been evacuated for Irene. Thus when Sandy occurred the next year, many did not evacuate. That made it worse for the people living in the area. Sandy was worse then Irene because of the combined effects you noted and many weather forecasters noted beforehand.
While Bloomberg is at a level of horse manure, Irene did some serious damage in my neighborhood. The three houses next to me lost everything. The brunt of the storm destroyed upstate NY, CT and VT. It paled in comparison to Sandy but it was a major weather event.
I still can’t get over that POS who believes God or karma gave NY what it deserved and am frankly disappointed that no one else here called out this piece of traitorous vermin.