cataract on the west slope of the Sierra Nevada in Yosemite National Park, east-central California, U.S. It lies 150 miles (240 km) east of San Francisco. With a drop of 1,430 feet (436 m), it is one of the highest waterfalls in the world and is one of the park's most scenic attractions. Reaching a peak volume during May and June, it is fed mainly by melting snow; hence it may be dry for part of the year.