New York City got hit with widespread power outages in the

wake of Hurricane Sandy, with some 793,000 in the metropolitan area without

power, according to a Con Edison spokesperson.

Getting the power back won't be easy, largely because of the

flooding. It will probably be at least a few days before power can be

restored. "We're focusing on damage assessment," the spokesperson

said. Con Edison Senior Vice President for Electric Operations John Miksad

told CBS

New York that it was the biggest storm-related power outage in the

company's history.

Con Edison serves 3.2 million people in Westchester County

and New York City. In Westchester, some 180 roads are closed by downed trees,

so crews are going to have a tough time getting to places where trees have hit

power lines.

Anatomy of a Power Outage

The utility company cut power for customers south of Wall

Street at 7 p.m. on Monday. The same thing was done in parts of

Brooklyn. Deliberately

cutting the power was necessary as it's more dangerous to have current flowing through equipment


gets flooded — it can cause short circuits, fires, and other


Con Edison has an outage map

showing areas that are currently without power.

In New York City, the water has to be flushed out

of the flooded areas first before power equipment can be checked to be sure it's safe to run

current through. And the current to damaged equipment has to be shut down before

repairs can be made.

Odds are, if your area is served by underground lines, the

power should be back in four days; it will be a week or so for those served

by telephone poles. But those timelines are approximate; a lot will depend on

what the situation is locally. Anyplace there is standing water and downed power lines is dangerous; there have been 10 fatalities in New York City and Mayor Michael Bloomberg said in a press conference that a few were the result of people stepping into puddles near live power lines.

While it's certainly inconvenient, there is also another

logic to cutting the power in certain areas. When power is suddenly cut off in

one part of the system, it increases the current flowing through other parts

of the grid. That can overload the system causing more damage and an even wider

power failure.

Could A Smart Grid Curb Blackouts?

Another twist for some Manhattanites is losing the steam

heat system. In New York, many buildings are heated by a system of steam pipes

from a central plant. Con Edison had to shut down the system in some areas

because if water hit the pipes, the temperature difference would weaken the

metal, which could lead to explosions.

The loss of the steam system means that some people will be without heat and

hot water.

At about 8:30 p.m. last night a power

plant explosion on the eastern shore of Manhattan was caught on video,

though a Con Edison spokesperson said it wasn't clear whether it was caused by flooding or flying debris. After the explosion, power was out south

of 39th street. The substation served about 250,000 people.

Photo, top: The Brooklyn Battery Tunnel floods after a tidal

surge from Hurricane Sandy (Allison Joyce/Getty Images); bottom: Downed trees in lower Manhattan block streets (Andrew Lichtenstein/Corbis)