The Hudson Canyon is a submarine canyon that begins from the shallow outlet of the estuary at the mouth of the Hudson River. It extends out over seaward across the continental shelf finally connecting to the deep ocean basin at a depth of 3 to 4 km below sea level. It begins as a natural channel of several kilometers width, starting as a 20-40 m depression at Hudson Channel southward from Ambrose Light, then carving through a deep notch of about 1 km depth in the shelf break, and running down the continental rise. Tidally associated flows of about 30 cm/s (1 km/h) up and down the deeper parts of the canyon have been recorded. As silt, sand and mud are carried down the Hudson River, they flow into the canyon and out into the deep sea.