Hurricane Irene, currently category 2 on the Staffir-Simpson scale, looks like it's heading straight for New York City. Both the NYC and New Jersey emergency management agencies have published maps (pdf) showing the likely flood zones for various categories of hurricanes. They're scary.
I used to live in Brooklyn Heights, N.Y., and Hoboken, N.J. Both areas would be affected by a category 1 hurricane. My place in Hoboken, in fact, was only 2 m above sea level. My stuff would probably be OK—I lived on the fourth and fifth floors—but a moderate storm surge would likely flood the entire city of Hoboken, and make it impossible to live there for weeks.
I hope all my friends in the New York Metro are taking reasonable steps to protect themselves and whatever stuff they can get out. It's going to be a wet weekend in the Northeast...
Update, 13:27 CDT: New York City and the surrounding area have decided to shut down all commuter train, subway, and Amtrak service in the region starting at noon tomorrow.