Coming up: Big Hudson River tides

(Photo by Will Dendis)

Extremely high Hudson River tides start this Sunday and peak Tuesday, April 27. That’s because Monday’s Full Moon happens just before it reaches its closest approach of the month. And its third nearest meeting with Earth of the entire year, missing second place by just 42 miles.

The best place to see these extraordinary tides is the Bay of Fundy where the seas move up and down an astonishing five stories. But you can observe nice tides here too, without even going to the ocean. In our region one major treat is to stay at the marvelous B&B at the Saugerties lighthouse, restored a couple of decades ago by a group called the Lighthouse Conservancy. In the morning, the lighthouse keeper will cook you breakfast while you watch the magic wrought by the Moon’s invisible fingers, as the river dramatically rises and falls, changing the peninsula you’re on into an island. If you can’t make it to Mont St. Michel in France, that’s the next best thing.

The tides of the Hudson are not paltry; they typically range by four or five vertical feet with each in-and-out breath of the waters. When an Atlantic storm raises the seas at the mouth of the Hudson, sensors at Battery Park sound the alarm, and an additional two feet can arrive upriver some six hours later. This illustrates the first oddity, since six hours is also coincidentally the interval from high tide to low tide around the world. So whenever it’s high tide at the Battery, it’s the very hour of low tide up here in Ulster, Dutchess and Columbia county.


All this happens because the river is barely higher than the Atlantic, while the daily tides push its surface from one foot below mean sea level to 5 1/2 feet above. The river›s tides move at 17 mph from Manhattan all the way up to Troy, where they end ingloriously at the dam. From Poughkeepsie north, no salt water remains.

Although the tide progresses at 17 miles per hour, the water itself moves much more slowly. Anyone watching a piece of floating debris will see it progress northward with the incoming tide, and then later observe it flowing south. It may repeat the zig-zag process, which is why it would take someone in an inner tube over half a year to float from Albany to Manhattan.

The highest tides usually happen a day or two after New and Full Moon. That’s why the timing is now perfect for huge tides. One day after Monday’s Full Moon, just when the tides should maximize, is exactly when the Moon comes to this unusually close perigee. It’s a watery clockwork worth observing firsthand. 

Some months it’s the Full Moon, on others the New Moon that’s the largest influencer of our river tides. But currently — with lunar phase and distance synchronizing so well — it’s right now.