The EFAS medium-range flood forecasts provide an overview of flood probability over the coming 10 days. They are created by comparing the EFAS forecast simulations with EFAS flood threshold levels. These flood threshold levels are calculated for every grid cell, based on a discharge time series simulated by the operational LISFLOOD hydrological model from observed meteorological data.


EFAS medium-range flood forecast products are displayed as colour coded overview maps and time-series information at reporting points that can be viewed under the ‘Flood Summary’ layer of the mapviewer. There are five main medium range products:

The EFAS medium range forecasts provide the fundamental information upon which Informal and Formal Notifications are generated and then distributed to the EFAS partners: 

 

EFAS hydrological forecasting chain
EFAS hydrological forecasting chain

N.B. EFAS medium-range flood forecasts produced at least 30 days earlier are freely available to view. Real-time EFAS medium-range flood forecasts are only available under certain conditions. Visit the EFAS data access pages to learn more on data restrictions.

The 'Reporting Points' layer
The 'Reporting Points' layer

 

Additional local information associated with each flood forecast layer (except for the ‘Flood Probability’ layers) is available from the Map Viewer as pop-up plots when clicking on the points. They display information such as Point Geographical Information, Forecast Summary and Flood Hydrographs. Read more about the pop-up plots and reporting point criteria in the Wiki under EFAS Reporting Points.

Furthermore, spatially distributed information along the river network can be visualized in the Map Viewer (see the image below). This feature highlights locations along the river network where EFAS forecasts a flood, presenting both the flood severity level and the probability of the impending flood. This layer combines the 2-year (yellow), 5-year (red), and 20-year (purple) total (combining all models) exceedance probabilities.

Spatially distributed information along the river network, showing both flood severity level and flood probabilities.
Spatially distributed information along the river network, showing both flood severity level and flood probabilities