Yosemite at a Glance: Waterfalls

There are daily fluctuations in the streams, rivers, and waterfalls of Yosemite. Flow increases in the afternoon when daytime temperatures are at their peak and snowmelt is highest. A sudden afternoon thundershower can have the same effect by replenishing soil moisture and causing rapid runoff through rocky basins.

Geology
Waterfalls

Dramatic Changes

During winter, sunny days between storms keep the falls in the valley at a trickle; they are transformed into pillars of ice by freezing night temperatures. The Yosemite Falls ice cone forms when water spray, frozen to the granite wall, loosens as it is warmed by the sun and spills to the base of the upper falls.

Water that does not freeze builds up on the cone, and as the temperature continues to rise, the water falls straight into the cone like a reverse volcano. The cone can grow to heights of 250 feet and can cover up to four acres.