Sources: Esri, Airbus DS, USGS, NGA, NASA, CGIAR, N Robinson, NCEAS, NLS, OS, NMA, Geodatastyrelsen, Rijkswaterstaat, GSA, Geoland, FEMA, Intermap and the GIS user community
The outer circle is forecast stage, the inner circle is observed stage. In this example, the river is in the action stage, but is forecast to become a moderate flood.