We can’t forget that, next to rocks and boulders, the most abundant thing a glacier carries is water, in fact billions and billions of cubic feet of water are contained in a glacier as big as the Wisconsinan at it’s peak. Glacial ice is about 90 percent water and the upper layer of the glacier, where it’s mainly compressed snow, is about 50 percent water. When these huge continental glaciers were “alive” and all that water was “locked up” as ice one can only guess at how far the sea level dropped. It must have been a dramatic lowering of ocean levels just as when the glaciers melted how fast and how much the sea level must have risen. For our purpose, though, I’m thinking about the impact of the water the continental and local glaciers represent in terms of the natural history of the White Mountains.
Richard Goldthwait thinks the continental glacier took between 100 and 1000 years to completely melt back away from the White Mountains. The melt water flowed in three directions. It flowed east towards the Atlantic via what’s now the Androscoggin Valley, south towards the Atlantic via the Pemigewasset (Merrimack) and Saco Rivers, and west, also to the Atlantic via the Ammonusuc, Israel and Connecticut Rivers. The melt water created vast lakes such as Glacial Lake Hitchcock that was a huge body of water a 100 miles stretching from near Northampton, MA, northwards to Littleton, NH.
In the photo above it's possible to 'feel' how the melt water shaped the landscape, the downward sloping valley, softening it, and you can sense how the water founds its way towards an established 'bed' as it sought out the Atlantic Ocean there in the distance.