In an Unexpected Storm, a Horror Movie Made Real From a single corner in Lower Manhattan on Monday night, you could see three centuries of the built city, the work of human hands meant to stand against time and tide. A few steps from the corner of Greenwich and Spring Streets is the Ear Inn, constructed in 1817; with the streetlights snuffed out, its tall glassed neighbors also dark, the Ear was one more dim shape. With a slight shift of the eyes, you could look a mile south on Greenwich before seeing the only lighted structure downtown, the giant skeleton of the new tower at 1 World Trade Center. For buildings ancient and modern, devastation arrived in the same breath on Monday night: not in howling winds, but in the murmur of the Hudson River. At Spring Street, the river waters carried over the east bank, moved across West Street, spread past Washington and Greenwich Streets and then most of the way to the street named for the river, Hudson. That is: the river moved 1,200 feet inland, nearly a quarter-mile. We have reached the moment of the instructive catastrophe, our vulnerability bared by forces that we can no longer pretend are some civil engineer's bad dream. In the summer of 1991, I watched a kind of horror movie. Federal emergency planners ran a slide show of pictures of familiar New York sites that had been doctored to show the effects of a Category 4 hurricane on the city. The entrance to the Brooklyn-Battery Tunnel, nine feet underwater. Nathan's in Coney Island, fully submerged. Diapers floating off the shelves at the Toys "R" Us on the Belt Parkway in Brooklyn. Kennedy International Airport, 24 feet underwater. It seemed far-fetched. On Monday night, more than two decades later, I stood in Hudson River water at Hudson Street, and have the wet sneakers to prove it. The governor, Andrew M. Cuomo, got on the phone Tuesday afternoon after visiting the World Trade Center site and sounded as though he could scarcely believe what he was saying. "The new platform at the PATH station at ground zero has five feet of water up to the platform," Mr. Cuomo said. It goes all the way back to Jersey. That's the full length of the PATH tube. He paused. "That is something we're constructing now," he said. The Brooklyn-Battery tunnel, you go in 100 yards, the water goes right up to the ceiling. New York is an archipelago, four boroughs on islands and a fifth on the mainland; the natural harbor is its Genesis fact, the reason that European settlers made a port city here. To succeed, they had to take the measure of the tides and add a margin for surges. The reckonings of history are going stale. "They call it the hundred-year flood, because it's only supposed to happen every hundred years," Mr. Cuomo said. I told President Obama, we have a hundred-year flood every two years. The existence of climate change is, in overwhelming scientific consensus, accepted as fact, despite near silence about it in the presidential campaigns; the extent of its connection to extreme weather events remains a much-less-settled matter. "I don't call it "global warming" because you trigger a whole political debate," Mr. Cuomo said. But the frequency of extreme weather is going way up. Banks, he noted, have maps of areas that may be affected by climate change. "It's amazing how much of Brooklyn and Queens goes underwater so quickly," he said. We've just ignored it. We've just been blind to it. During the day, he floated a few solutions, including sea gates around New York Harbor that would, in theory, temporarily hold back mighty walls of water. These would be undertakings of many billions of dollars, and Mr. Cuomo said they would take years to build - once they were started. "I don't think most people would agree with me at this point," he said. First you have to convince the citizenry, then get the elected officials to move. Much of the technical city, as built, is below sea level, and the mouths to the tunnels are on low ground. Monday night, water on West Street near the trade center was five feet high, Mr. Cuomo said. "When this space was built, there was no assumption that the river could overcome the bank," he said. The door of the Ear Inn is about five feet east of where the Hudson shoreline was in 1817. On Monday night, two centuries later, the river rolled past the door and kept going two more blocks.