Ice Circles in the Hudson River in New York City

Last weekend after leaving the New York Travel and Adventure trade show, I walked past an icy section of the Hudson River off the West Side Highway near Pier 57 at 14th Street. This was after the arctic cold snap hit New York City and partially froze the Hudson River on January 21st & 22nd with overnight low temperatures around 12 degrees.

It was dark, but in the water below I could see these glistening round ice circles. They were mesmerizing. It was cold, but I couldn’t stop looking at them.

The Hudson River is situated between New Jersey and New York City. It’s a little over a half mile wide and on the other side here is Hoboken, New Jersey. The last time I recall the Hudson River partially freezing was in 2014, which coincidentally I wrote about in February 2024 (the ten year mark). But I don’t remember seeing these nifty little ice circles.

Ice circles, also known as ice disks or ice pans are a “rare natural phenomenon that occur in slow moving water. They are thin circular slabs of ice that rotate slowly on a body of water’s surface” and form these neat, almost perfect circles.

And the physics explanation: “Ice circles tend to rotate even when they form in water that is not moving. The ice circle lowers the temperature of the water around it, which causes the water to become denser than the slightly warmer water around it. The dense water then sinks and creates its own circular motion, causing the ice circle to rotate.” The twisting around effect is what gives them their circular shape.

Standing there watching it in the dark I imagined this might be what it feels like to be in Antarctica surrounded by ice, except the pieces might be larger. The glowing green lights that look like the Northern Lights are from the golf range at the Chelsea Piers Sports Complex.