Data source: USDA NRCS National Water and Climate Center, SNOTEL network. "Snow water equivalent" is the depth of water that would result if the entire snowpack melted instantaneously. "Precipitation Accumulation" is the station's own water-year running total (resets each October 1) -- exactly as NRCS reports it. SNTL stations report full daily records; COOP and SNOW-course stations only report monthly totals; some networks (e.g. Bureau of Reclamation reservoir sites) are listed for reference but have no data available via this API.