A warning issued by the NWS to warn of river flooding which is imminent or occurring. A flood warning is issued when a river first exceeds its flood stage, and it may be reissued if a new river forecast for a forecast point or reach is significantly higher than a previous forecast.

Advance notice that a flood may occur in the near future at a certain location or in a certain river basin.

Flooding conditions are actually occurring or are imminent in the warning area.

Advance notice that a flood may occur in the near future at specified locations.