United States Department of Agriculture
Natural Resources Conservation Service
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National Water and Climate Center

Snow Surveys and Water Supply Forecasting

Agriculture Information Bulletin 536

The beauty of snow is fascinating, and millions of Americans enjoy the snow-covered landscape as a playground. But beyond its esthetic and recreational appeal, snow plays a vital role in our lives as a primary source of the water supply in the Western United States.

Increasing and often conflicting demands for water in the West have heightened public awareness of the need for sound management decisions concerning water. Although the West's high mountain ranges hold a vast snowpack that provides 50 to 80 percent of the year's water supply, nature cannot be relied upon to provide an uninterrupted, dependable supply of meltwater to meet all the downstream requirements. To moderate this variability, reservoirs and canals have been built to serve the growing needs of agriculture, industry, and communities. But successful water management begins with an adequate knowledge of the primary source of water in the West: snow.

Obtaining accurate and timely information on the extent and water content of the mountain snowpack requires specially trained people and unique equipment. The Federal, State, and private cooperative snow survey program directed by the U.S. Department of Agriculture's (USDA) Natural Resources Conservation Service (NRCS) has met those needs since the mid-1930's and continues to evolve in response to increasing demands of water users. With a computerized data collection network and forecast system, the program also fills many other requirements for hydrological and climatological data useful in natural resources management and research.

This booklet describes the cooperative snow survey program. It is intended to provide the general public as well as water resource professionals with a better understanding of the importance of snow, snowpack surveys, and water supply forecasting in natural resources management.