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The EFAS Reporting Point layer consists of a queryable map, with pop-out windows providing additional information.

Reporting Point map

The figures below explain the Reporting Points map layer.

The reporting points are created using the following process. For each NWP-driven forecast, a flood probability is computed for each flood threshold using the maximum forecast discharge value over the 10-day forecast horizon. This flood probability is only computed on the large rivers with an upstream area > 250 km2. Very dry area are also excluded by excluding the rivers with a 1.5-year return period below 1 m3/s. A total probability of exceedance is computed from these maximum forecast probabilities (from DWD-HRES, ECMWF-HRES, ECMWF-ENS and COSMO-LEPS). The weights of the forecasts in the total probability are equal but, in order to avoid the predominance of deterministic forecasts in the region where COSMO-LEPS is not available, we impose a ratio of 50% deterministic, 50% probabilistic in the computation of the total probability. The persistence probability is then calculated by averaging the total probabilities from the current and the previous forecast. Dynamic reporting points are finally created (and their alert levels are computed) based on the following rules:

  • 20-year return period: persistence probability > 30% and upstream area > 1000 km2
  • 5-year return period: persistence probability > 30% and upstream area > 1000 km2

  • 2-year return period: persistence probability > 50% and upstream area > 1000 km2

Alert levels are also computed for static reporting points where hydrological metadata information is available. The rules are different for these points:

  • 5-year return period: persistence probability > 10% or at least 3 COSMO-LEPS members exceeding the 5-year return period threshold, and upstream area > 1000 km2

  • 2-year return period: persistence probability > 10% and upstream area > 2000 km2

Alert levels are only computed for reporting points with past persistent forecasts.

Pop-out windows

Additional local information associated with each flood forecast layer (except for the ‘Flood Probability’ layers) is available from the mapviewer as pop-up plots. They display information such as:

  • Point geographical information - e.g. country, basin, river and station name.

  • Forecast summary - e.g. forecast issue date, probability values, persistence values, tendency and time to peak.

  • Flood hydrographs.

  • Summary diagrams of catchment meteorological forcings.

  • Consistency diagrams: show the evolution of the forecast signal over time. They display the forecast threshold exceedance for each return period threshold (1.5-, 2-, 5-, 20-year) for each day of the forecast horizon for the latest eight consecutive forecast runs.

  • Real-time hydrographs (for certain points only): ECMWF-ENS EFAS forecast post-processed based on observed discharge. They also display the probability of exceeding a mean annual maximum discharge within the next 15 days.

Below are some graphical aids to help to interpret and use reporting points' feature information products (these can be found under the Flood Summary layer group - Reporting Points layer, when clicking on a point on the EFAS-IS mapviewer).




 





Restrictions

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.



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