Data Collection

Barring unforeseen bad weather, the work of the snow surveyor is fairly standard. A snow sampling tube with a cutter end is driven through the snow pack, measuring depth; by weighing the snow core, the water content (water equivalent) is obtained. The same points are sampled several times each winter to observe changing conditions throughout the season.

The original data collected by the various snow survey teams are transmitted to the Department of Water Resources. In addition to snow pack water content data, statistics on precipitation, runoff, and similar historic hydrologic data are collected.

This information is fed into a computer and, when correlated, enables the State to forecast snow melt runoff in California. The forecasts, published on a monthly basis from February through May, are used by a variety of people and agencies throughout the State, such as public utilities, agricultural interests, project operators, municipalities, recreationists, and the news media. On the basis of information gathered from the network of snow sensors, the forecasts are updated weekly for key basins in the Central Valley.

* How a Survey is Made
* Snow Pillow
* Rain on Snow
* Depth and Density

Next: Impact of Forecasting