Experts have warned that it could take the New York City subway system three full weeks to come back online.
Mayor Michael Bloomberg announced on Tuesday that the subway service would be shut down until Saturday or Sunday – a total closure of six to seven days.
But a group of Columbia University researchers analyzing the effects of a smaller hurricane or tropical storm suggest that it would shut down the subways for 21 days.
The predictions came in a report authored by Klaus Jacob, a geophysicist who specializes in disaster management, that examined the effects on the city’s transportation infrastructure of a 100-year storm.
And the model used a storm less powerful than a superstorm such as Sandy.
Limited bus service began again on Tuesday and was expected to expand throughout the week.
Trains stopped running at 7:00 p.m. on Sunday as the MTA preemptively closed down service for only the second time in its history.
The closure was an effort to secure the subway system against the impending storm, but massive damage came anyway.
The tunnels beneath the East River between Manhattan and Brooklyn flooded and dozens of stations across the city were inundated by the storm surge that rose water levels by 13 feet.
Dr. Klaus Jacob and his researchers used a lesser storm as a model for their report – one that has only a one percent chance of happening in any given year.
A statement from the MTA on Monday said Hurricane Sandy was the worst disaster in the subway’s 108-year history.
Dr. Klaus Jacob’s report estimated that a hurricane hitting nearby could result in 1billion gallons of water flooding each of the subway’s 14 tunnels that run under the East River.
Each tunnel was expected to take at least five days to pump dry.
The study’s 21-day estimate includes the time Dr. Klaus Jacob predicted it would take city workers to bring the subway system back to 90% function.