CFS (Cubic Feet per Second)
The standard unit for river discharge in the United States, measured by USGS gauges across the country. One CFS = the volume of one cubic foot of water passing a fixed point per second.
CFS readings on their own are not interpretable for fishing — 500 CFS could be "blown out" on a small creek and "low and clear" on a big river. The useful interpretation is each river's percentile rank: where today's reading sits in the river's own historical distribution. Steelhead Addiction publishes both the raw CFS number and its percentile rank for every covered river. USGS publishes raw gauge data at https://waterservices.usgs.gov/.
