As silt, sand and mud are carried down the Hudson River, they flow into the canyon and out into the deep sea.
[2] The canyon was last exposed during the last ice age, over 10,000 years ago, when the sea level was about 120 m (390 ft) lower and the mouth of the Hudson River was near the edge of the continental shelf, about 100 mi (160 km) east of its present site.
The river discharged sediment that helped carve the canyon aided by underwater avalanches of mud and sand.
Recent maps of the canyon reveal tributaries of an extraordinary underwater drainage network that is strikingly similar to terrestrial rivers.
Tidal currents sweep up and down the channel; and on occasion, during big storms, cold ocean water is pushed up the Hudson Canyon to spread out on the shelf.