Like much of the U.S., New York City is in the grip of a bitter winter cold. According to a post by Scientific American‘s Larry Greenemeier, more than a century ago, the East River would freeze over every few decades, but ice floes are far less common these days. The river, which which is technically a tidal straight, can run in either direction, depending on the time of day, and its waters move in excess of five knots (forceful enough to have destroyed a set of energy-generating turbines installed on its floor in 2002). So in the many years that Greenemeier has lived on Roosevelt Island, which sits in the middle of the river, he has never seen ice form on its surface… until now. Below is a short video that he put together that chronicles the arrival of ice floes off the eastern coast of the island between February 16 and 21. Brrr!