An EFAS Formal Flood Notification is sent out to the affected EFAS partner if at least a 30 % probability is forecasted that one of the two probabilistic forecasts exceeds the 50 % of the total forecast probability exceeds the EFAS 5-year return period level for three consecutive model runs and if the start of the event is more than 48 hours and less than 7 days in advance with respect to forecast time (Example: for the forecast 2024-06-18 00 UTC the event should start from the run time of the model. Additionally, one of the two deterministic forecast needs to exceed the 5-year return period as well. 2024-06-20 00 UTC and before 2024-06-25 00UTC). The start of the event is when 50% of the ensemble, i.e. the median of the boxplot, exceeds the 5-year RP.
Formal Flood notifications can only be issued if the catchment area is larger than 2000 km21000 km2.
EFAS Formal notifications are sent to partners by e-mail. All partners within transnational basins receive the notification as a notice of a predicted event in the basin.
EFAS Formal Notification e-mail
The affected country and river basin as well as the predicted start and earliest peak of the event are indicated in the notification email. Probabilities of 5- and 20-y return period exceedances are taken from ECMWF-ENS or COSMO-LEPS, whichever is of higher value.
Forecast date refers to the model run when criteria were fulfilled. Using the link to EFAS IS, you can follow the event or leave feedback on it (see also section 4.4). Only one notification is issued for each event, after the notification it is on the partner to follow the evolution of the event.