Notification Criteria Abstract -  Jesus Casado Rodriguez 


New Notification Criteria - Conrad & Stefania Grimaldi 

Detailed description of the new notification criteria. 

The new formal flood notification criteria are:

1. Catchment part of Conditions of Access (CoA), i.e., within the EFAS partner region.
2. A catchment area of at least 1000 km².
3. A total probability of exceeding the EFAS 5-year return period of at least 50%.
4. The onset of the event will occur between 2 and 7 days from the forecast time. E.g., for the forecast 2024-08-13 00UTC, the event must start between 2024-08-15 06UTC and 2024-08-20 00UTC. The onset of the event is the first time step when the probability criterion in point two is fulfilled.

An informal flood notification will be issued when any of the criteria above is not met, but the forecaster deems that the authorities should be informed. To issue an informal notification, the exceedance probability must be at least 40% and the catchment area at least 500 km².

EFAS v5.2 - Updates to visualisations Juan Pereira Colonese & Corentin Carton de Wiart

As a consequence of the new combination method and the new notification criteria, the following EFAS products have been changed:

  • The layers previously called Flood Probability < 48 h and Flood Probability > 48 h have been renamed as 5-year exceedence < 48 h and 5-year exceedence > 48 h, respectively. These layers show the total probability of exceeding the 5-year return period in the current forecast. The layer corresponding to lead times larger than 48 h is used to issue formal flood notifications.
  • The Flood probability persistence layer has been renamed Flood probability. The new layer shows the total probability of exceeding three recurrence periods (2, 5 and 20 years), based on the grand ensemble and only the last forecast.
  • The Reporting Points is now based on the new flood notification criteria. As it is based on total probability, the label indicates only one exceedance probability value. Some minor changes affect the pop-up window:
    • A new grand ensemble hydrograph that combines the forecasts of all 4 NWPs.
    • The total probability in the forecast overviews is now based on the total probability.