In the spring, after all the avalanches are down and the snow is melting fast, then all the Yosemite streams, from their fountains to their falls, sing their grandest songs. Countless rills make haste to the rivers, running and singing soon after sunrise, louder and louder with increasing volume until sundown; then they gradually fail through the frosty hours of the night. In this way the volume of the upper branches of the river is nearly doubled during the day, rising and falling as regularly as the tides of the sea. Then the Merced overflows its banks, flooding the meadows, sometimes almost from wall to wall in some places, beginning to rise towards sundown just when the streams on the fountains are beginning to diminish, the difference in time of the daily rise and fall being caused by the distance the upper flood streams have to travel before reaching the Valley. In the warmest weather they seem fairly to shout for joy and clash their upleaping waters together like clapping of hands; racing down the cañons with white manes flying in glorious exuberance of strength, compelling huge, sleeping boulders to wake up and join in their dance and song, to swell their exulting chorus.