Rainbow Falls of the Ausable River

December 14, 2017


Photographer: Patti Weeks 
Summary Author: Patti Weeks 

December 2017 Viewer's ChoiceThe Ausable River originates high in New York state’s Adirondack Mountains at Mount Marcy, the highest point in New York state (elevation 5,344 feet or 1,629 m), and runs nearly 100 miles (160 km) before emptying into Lake Champlain, to the northeast. The river's rock bed is the 500 million-year-old, 520-feet (158 m) thick Cambrian Potsdam Sandstone, consisting of well-cemented, nearly pure quartz. Ausable is French for sandy and was originally written as Au Sable.

At the end of the Pleistocene Epoch ice age, about 10,000 years ago, the river carved a deep gorge, the Ausable Chasm with Rainbow Falls as its headwaters. This Chasm, a few miles northeast of Keeseville, New York, is only about 2 miles (3.2 km) long, but at places is as deep as 350 feet (107 m) and called by some the Little Grand Canyon of the East. It's been a popular tourist destination since 1870. The water level of the Ausable River and Rainbow Falls can vary considerably, becoming much higher following a storm or winter snowmelt. The falls were comparatively low at the time this photograph was taken, on October 7, 2017, exposing the thick, clearly horizontal layers of the Potsdam Sandstone.

Photo Details: Camera: SONY DSC-HX400V; Exposure Time: 0.0063s (1/160); Aperture: ƒ/4.5; ISO equivalent: 80; Focal Length: 26.1mm; Lens: 4.3-215mm ƒ/2.8-6.3.