Every day is a new day when it comes to the subway—you could be trapped on a train with no explanation for hour(s) or battling raccoons just to get to work on time. Or you could happen upon a subway entrance that's totally flooded to the brim on a clear fall day, like a magical urban cenote that makes you wish you brought your scuba gear.

Passerby Kaye Blegvad tweeted the above photograph with a simple plea: "MTA explain yourself." The MTA's social media team was quick to respond.

We're pivoting to submarines. ^JLP — NYCT Subway (@NYCTSubway) November 20, 2019

Ha ha. Then the MTA got serious:

But actually, we were testing a new "flex gate," which is a flood barrier that would allow us to seal off a subway entrance. We "test flood" the entrance for four hours to make sure it was installed correctly, which it was!



We're doing this because climate change is real. ^JLP — NYCT Subway (@NYCTSubway) November 20, 2019

The MTA further elaborated: "We're investing in capital projects around the system to prepare for the impacts of a changing climate. Here's another one that might interest you! We're always here to answer any questions you may have." The agency shared a link to a press release on how the MTA is working to protect the Coney Island Yard from climate change.

During Superstorm Sandy, multiple subway stations and tunnels were flooded and suffered damage that the agency is still trying to repair (yes, that's why the L train is being rehabbed).

In a 2019 report (PDF) that provided an update on resiliency work post-Sandy, the MTA noted, "At street level, we built flood gates into flood-prone train station entrances, while hatches and manhole covers were redesigned to withstand large volumes of standing water. Underground, marine cabling replaced the regular wiring in the under-river tubes to increase flood resiliency." For instance, the MTA spent $369 million to upgrade the South Ferry 1 station, which was flooded by nearly 15 million gallons of salt water and, across the system, they've been adding more flood protections, like "flex gates," to stations.

So that's why the Broadway station entrance was flooded for a few hours. "For a second it was very surreal," Blegvad said, describing her reaction to seeing the watery opening. "I thought the entire station must be flooded, then realized the other entrances were dry and kinda shrugged, thought 'oh, MTA,' figured it was some kind of maintenance thing. Only a few minutes later it sunk in how deeply weird it was!"

Or maybe it's the portal to the secret sea turtle subway system, as depicted in Deborah Brown's Platform Diving mural at the Houston Street station?