Rainbow Falls

The Grass River is one of the most well-endowed waterways in the western Adirondacks, sporting at least 15 named waterfalls along its various branches – though most of them not terribly large. The South Branch specifically harbors eight named waterfalls, and four of them are quite significant.
Rainbow Falls is the uppermost of the major waterfalls on the South Branch of the Grass River, and is the most geologically unique of the falls in the area. Here, like at Twin Falls further downstream, the river splits around a small island-like structure, with the majority of the river funneling over the major falls, and a smaller channel bypassing the main falls. However unlike at Twin Falls, in the case of Rainbow Falls, the smaller channel of the river doesn’t actually harbor a waterfall of any sort.
At the main falls the majority of the river funnels down to just 25 feet across and thunders 28 feet into a narrow gorge with sheer cliffs on either side, coated with copious volumes of spray ejected from the roaring boil at the base of the falls. The smaller channel simply bypasses the gorge entirely, and instead flows over a series of large boulders, tumbling one foot here, two feet there, but in all not resembling even rapids for the most part.
The South Branch of the Grass River drains from a basin which covers approximately 118 square miles upstream from Rainbow Falls, originating in many lakes, marshes, and wetland areas. The volume of the river will be good and the falls impressive at any time of year, but the falls will be at their most spectacular during the spring freshet from March to May.