Having lived in Brooklyn for four years (near Carroll Street station, a few blocks in on the F train), it is hard to imagine New York City functioning without its subway system, yet transit authority officials have no idea when they'll have it running again:

The giant storm Sandy wreaked havoc on the New York City subway system, flooding tunnels, garages and rail yards and threatening to paralyze the nation's largest mass-transit system for days.

[...] All seven subway tunnels running under the East River from Manhattan to Queens and Brooklyn took in water, and any resulting saltwater damage to the system's electrical components will have to be cleaned - in some cases off-site - before the system can be restored, MTA spokeswoman Diedre Parker said on Tuesday.

[...] About 5.3 million people use the city's subway system on weekdays. The system, which runs around the clock, comprises 21 subway routes linked by 468 stations, and stretches across 660 miles (1,050 km) of track.

For many of these 5.3 million daily riders, the subway is the only way for them to get to and from work. I didn't know anybody in the city who owned a car, and there's no way the bus system could even begin to pick up the slack.

You know how when it snows in Seattle, sometimes some buses don't run? Multiply that by infinity and you've got an idea of what's going on in New York.