Not much of a blackout?

34th street is midtown Manhattan. That is half of Manhattan Island. On a normal business day, that would account for about 2.5M people.
Not sure why you would be comparing Staten Island to Manhattan. Devastation wise, Staten Island is made out of wooden houses, Manhattan is made out of concrete and steel buildings. They aren't likely to be washed away. One big difference is Manhattan is not only exists above ground, most of Manhattan's utilities and mass transit exists below ground. Flooded, below ground.
Both Staten Island and lower Manhattan took a serious hit. (they are only across the bay from each other) Staten Island has about 450k people.