Yellowstone Lower Falls 308ft from Artist Point,Yellowstone National Park,Wyoming,USA 13th September 2011

Yellowstone Falls consist of two major waterfalls on the Yellowstone River, within Yellowstone National Park, Wyoming, United States. As the Yellowstone river flows north from Yellowstone Lake, it leaves the Hayden Valley and plunges first over Upper Yellowstone Falls and then a quarter mile (400 m) downstream over Lower Yellowstone Falls, at which point it then enters the Grand Canyon of the Yellowstone, which is up to 1,000 feet (304 m) deep.
Cascading from the 590,000 year old Canyon Rhyolite lava flow, Lower Yellowstone Falls is the largest volume waterfall in the Rocky Mountains of the United States.These falls (44°43′05″N 110°29′46″W) are 308 feet (94 m) high, or nearly twice as high as Niagara Falls. The volume of water flowing over Lower Yellowstone Falls can vary from 680 cu ft/s (19 m3/s) in the autumn, to 8,400 cu ft/s (240 m3/s) at peak runoff in late springtime.[citation needed] The flow rate of Lower Yellowstone Falls is much less than that of Niagara Falls, as the Yellowstone River is only 70 feet (21 m) at the point at which it goes over the lower falls, whereas the Niagara River is 2,600 feet (790 m) in width as it approaches the crest line of Horseshoe Falls.