Snowpack to River: A Canyon Road Trip

Following the Water

1In late June, Jaylen Brooks and his family drove into a mountain national park in the western United States. The road climbed through pine forest toward snowy peaks, then dropped into a deep canyon where a fast, muddy river roared between layers of red and tan rock. At the bottom of the canyon, the river flowed into a long lake.

2At the visitor center, a ranger showed Jaylen two sets of data. High on the mountain, at about 3,000 m, a weather station measures how much water is stored in the snowpack, the layers of snow that build up over the winter. The station reports the depth of water the snow would make if it all melted. Down at the park entrance, a stream gauge measures how much water flows past each second in the river. The ranger added that summers in the park are mostly dry, with only a few short thunderstorms.

3The ranger explained that some of the melted snow does not run straight into streams. Part of it soaks into soil and cracks in the rock and moves slowly downhill underground, reaching the river weeks or months later. The pine forest also takes up water through its roots and releases water vapor from its needles.

4Beside the lake, the visitor center keeps a shallow metal pan of water. Each day a ranger measures how much the water level in the pan drops from evaporation and refills it. A display shows the average daily drop for four months of the year.