Something of great power traveled through the Hudson River Valley; but in this case it was not the renowned adventurer and explorer Henry Hudson but the biblical forces of mother nature herself in relatively recent geological past.  This all happened in essentially during the great retreat of glaciers over North America 13,000 years ago; a product of global warming which ironically may have even triggered a cooling climate change event due to it’s mass and scale.

Three major events in particular are connected to, and paint the picture of a huge prehistoric lake three times the size of the present-day Lake Ontario. These events were caused largely by crashing through the gigantic ice dam holding in the lake thereby flooding the largely dry Hudson River Valley with a violent torrent of water. Thus paving a path all the way to the North Atlantic leaving a carved out valley and car sized “drop stones” in it’s wake.

The trio of events are broken into three names “The Mohawk Flooding”, “The Adirondacks Flooding”, and “St. Lawrence Sea Flooding” in this article.

The Events

First Event: Mohawk Flooding

This all starts some 22,000 years ago at the ice sheet peak when most of New York was locked up in ice. This was the start to the glacial melting period where the ice sheets were retreating North over the subsequent thousands of years. Between 14,500 an 13,800 years ago, with the ice retreating enough from the Mohawk Valley, an opening was created allowing an outlet for the lake of water behind it (Lake Iroquois). This routed melt water down the “IroMohawk” River into later, lower stages of Lake Albany in the Hudson Valley (see A above #1). This sent incredibly powerful water flow at a rate of at least 1.5 million cubic feet per second flowing down and through New York (See this video of 80,000 cfs) cutting massive potholes into the bedrock. In 1867 construction workers discovered a mastodon in one of these potholes on the Mohawk. It was dated at 12,9K to 13K years proving the minimum age for the pothole exposure.

Second Event: Adirondacks Flooding

Roughly between 13,400 and 13,100, a small period of 300 years, another notable event happened; the ice sheets retreating North finally opened up the St. Lawrence Valley (see B #2). This rerouted much of the flow of glacial lake water around the Adirondacks and down through NY. Sediments which are normally very small were found related to the event to be the size of large vehicles for example down in the New York City basin. These drop stones are identified because they do not belong in their found locations (glacial or sediment debris).

Third Event:  St. Lawrence Sea

Between 13,100 - 13,000 continued ice melt opened the St. Lawrence valley causing Atlantic water flooding and thus creating the Champlain Sea. See photo above (B). Interestingly in a process called post-glacial rebound, the land which was massively depressed down from the weight of the ice sheets recovered by rising up to normal levels and sending the sea water back into the Atlantic.

These events carved out the Hudson River and shaped New York to the way it is today. The consequences of these events were far reaching. Some experts theorize that the massive amounts of glacial melt that flowed out of New York disrupted the global conveyer belt of the ocean, which normally circulates the warm tropical waters northward, thus creating a global cooling period. This is detected in the vast changes in the vegetation of that period of time.