The flooding from "Frankenstorm" Sandy has been everything New York City was expecting (if not worse), and it looks like the long term effects could be serious.

The subway was closed today and looks likely to be definitely closed tomorrow, but that may just be the beginning. This photo, tweeted out by Port Authority NY + NY, shows how bad the situation is at underground stations.

Flood waters rush in to the Hoboken PATH station through an elevator shaft. #Sandy twitter.com/PANYNJ/status/… — Port Authority NY&NJ (@PANYNJ) October 30, 2012

MTA workers are already saying it could take until the end of the week to have the subway running again, but no-one is really even sure of that. The WSJ explains that saltwater has a particularly bad effect on the subway:

Salt can eat at motors, metal fasteners and the electronic parts, some many decades old, that keep the system running. Salt water, and the deposits it leaves behind, degrades the relays that run the signal system, preventing train collisions. Salt water also conducts electricity, which can exacerbate damage to signals if the system isn't powered down before a flood.

The NYC subway has been flooded before (during the nor'easter of 1992) and service was brought back to most lines within days. However, the same storm flooded PATH trains — which were forced to remain closed for 10 days after the storm.

So how long will it take? One MTA official has given a rough estimate — and it wasn't exactly encouraging:

14 hours to 4 days to pump water out of these subway tunnels per an MTA official on WCBS. No idea how long it will take to restore service. — Harry Enten (@ForecasterEnten) October 30, 2012

UPDATE: MTA chairman Joseph J. Lhota has released a statement. He says that the storm was the worst disaster the NYC Subway faced in 108 years, but did not give a timeline for reopening.