Cities 101: Why Is the Ice on the Hudson River Flowing Both Ways?

This winter, with New York City’s Hudson and East Rivers particularly frozen (and sometimes trapping the ferries), New Yorkers are getting a first-hand glimpse at, well, nature. In-the-know New Yorkers like to point out that the East River is not actually a river, but is an estuary, meaning that waters come in from multiple sources, including salt water from the sea. On February 17th, the East River Ferry published an explanation, sharing how the tidal patterns cause unpredictable ice flows writing, “the tide changes multiple times per day, enabling ice to enter from different major bodies of water, making it nearly impossible to predict what it’s going to do, or where it’s going to be.” But what about the Hudson River?

From the Untapped HQ, we’ve been watching the sheets of ice flow south, then north, reversing depending on the day. Turns out the Hudson River is also an estuary, and New York State Department of Environmental Conversation even goes so far as to say that “the Hudson is more than it seems.” The Hudson River actually “feels the ocean’s tidal pulse all the way to Troy,” 153 miles from the New York Harbor, and almost half the length of the 315 mile river. Rising tides will push the current towards Troy, and falling tide will move the water back towards the harbor. Every 24 hours, there will usually be two high tides and two low tides.

As we write this, the water is moving south again. Next, discover why the Staten Island Ferry sometimes heads in the wrong direction, up the Hudson. Check out 13 architectural sights to see when on the Hudson River and 10 on the East River.