There's a massive tropical storm headed to New York, one that may flood the subway. What most people don't know is that we depend on just 700 fragile water pumps to keep the tunnels dry - some a century old.
In fact, if someone powered down all these pumps tomorrow, the entire subway network would be inundated in just a few hours. To give you an idea of how complex and massive this system is, it pulls 13 million gallons of water out of the subway on any sunny day. No rain. Not even a single drop of water from the sky.
On a rainy day, it is absolute madness. To the point where the MTA - NYC's Metropolitan Transportation Authority - lives in permanent panic, fearing events like Nicole, the tropical storm system that is approaching the little town blue right now. "At some point, it would be too much to handle," said the head of the hydraulics team back in 2006, Peter Velasquez Jr, "you've got rain plus wind. It basically would shut down the system. You hope not. You pray that it doesn't."
This means that their hydraulic team - less than 200 people - are now on full alert, ready to intervene and install additional portable water bumps in whatever stations are needed. This is not an easy task. When the water reaches a certain level, it touches the third rail, which carries 625 volts. That makes the water extremely dangerous for these workers.
Back in the 1990s, a water main broke open, completely flooding the station at 125th St and St Nicholas Avenue. They had to send scuba divers to fix it and use a diesel-powered train car to take the water out. It took an entire week to drain the station, extracting 10,220 litres per minute. That's more than 100 million litres.
But you don't need to fully inundate the tunnels to take the subway system out. The water flooding could take out entire lines if the pumps fail to keep the levels below their safety limits. In 2004, the subway system stopped after Hurricane Frances spewed two inches of rain per hour over the city. In 2007, things stopped again. Then Governor Eliot Spitzer declared that "the cause of the cascading outages across the mass transportation system this morning was the inability of our drainage system to handle what was, we believe, three inches of rain within a one-hour period".
Not much has changed since then. The MTA's drainage system still can only slurp 1.5 inches of rain per hour, which is much, much less than what Nicole is bringing: A maximum 10 inches of rain per hour, with winds up to 100km/h. It kind of sounds like Velasquez's It sounds like Velasquez's You hope not. You pray that it doesn't scenario.