The service is provided by the U.S. National Water and Climate Center (NWCC), a division of the U.S. Department of Agriculture. It gives access to the AWDB (air and water database) which documents measurements of soil, water, and climatic conditions. Datasets are compiled by automated systems for measuring snowpack and stations in the Soil Climate Analysis Network (SCAN). Other measurements of snow accumulation and available water supplies are also included, such as streamflow and reservoir levels.
API methods support queries against the AWDB datasets. Specific methods give access to resources like the SNOTEL (SNOw TELemetry) climate service, more general indexes of climate conditions, National Weather Service COOP stations, 30-year normal levels for some measures, etc.