Gov. Andrew Cuomo on Tuesday said the World Trade Center site had suffered extensive flooding as a result of Superstorm Sandy and that damage to the construction work that is ongoing there could be in the billions of dollars. "What I saw last night in downtown Manhattan were some of the worst conditions I had ever seen," Gov. Andrew Cuomo said during a press conference on Tuesday morning, providing the first official description of the impact of the storm at the WTC site. "The Hudson River was literally pouring into the Ground Zero site with such a force we were worried about the structure of the pit itself." Patrick Foye, the executive director of the Port Authority of New York and New Jersey and the bi-state agency's top New York official, said he doubted the storm surge had caused any structural damage at WTC site but that equipment and electrical systems being installed may have been damaged by the flood waters. "There was a substantial incursion of water," Mr. Foye said. "I think it's fair to say that salt water and modern electrical equipment don't mix well. We don't expect structural damage but damage to equipment. That assessment is underway and is a high priority." Mr. Foye said that West, Washington and Cedar streets, roadways that surround the WTC site, were all flooded during the storm. The storm surge swept into the WTC site, a construction pit largely open to the elements, primarily through the Vehicle Security Center on the southern end of the project. The security center will have ramps to allow traffic to pass underground via subterranean roads and parking areas. It appears those ramps served as a chute for the storm's oncoming water. The WTC site is especially vulnerable to flooding because its located in low lying neighborhoods. Metropolitan Transportation Authority CEO Joseph Lhota said in a press conference Tuesday morning that the nearby South Street station at the southern tip of Manhattan had been completely flooded during the storm. Mayor Michael Bloomberg on Tuesday said that every major under-river subway tunnel had been flooded by the storm and that the subway system would be "closed until further notice" and that "no firm timeline" had been set for its reopening. He said he hoped some buses could begin running later Tuesday. The mayor said that restoring mass transit and electricity to the 60,000 city residents currently without power were the city's two biggest challenges.