In January 2021 the European Flood Awareness System (EFAS) publishes an interesting article on its website in which it takes stock of formal, informal and flash flood notifications throughout 2020 bse on the work carried out by Eric Sprokkereef, from the Dutch Ministry of Infrastructure and Water Management (RWS).
Figure 1: Number of EFAS formal (red), informal (yellow) and flash flood (blue) notifications issued in 2020. Image taken from EFAS
Among the conclusions, the total number of EFAS notifications in 2020 is 2213 (including formal, informal and flash floods), almost double that of 2019, considered a record year for flood notifications.
By periods and geographically, the last week of February with floods in the United Kingdom, at the beginning of March in France, the second and third week of May with large floods in the Pyrenees (France and Spain) and the period from the end of May to Early June with snow melt driven floods in Finland, Norway and the Russian Federation. The month of December was characterized by heavy rainfall, causing many flash flood notifications in Italy, France, Spain, the British Isles and the Balkan Peninsula.
Figure 2: Total number of EFAS formal (red), informal (yellow) and flash flood (blue) notifications issued per year from 2013-2020. Image taken from EFAS
It is significant that since the last 8 years, 2020 has been the record year for all types of notifications, but especially for flash floods.
What are Formal, Informal or Flash Floods Notifications for EFAS?
A daily overview is sent to the Emergency Response Coordination Centre (ERCC) of the European Commission which contains information on ongoing and forecasted floods in Europe as reported by the national services and forecasted by EFAS.
An EFAS Formal Flood Notification is issued when the probability of exceeding critical flood thresholds are forecasted more than 2 days ahead in a river basin with a minimum upstream area of 2000 km2 where there is EFAS partner.
Formal flood notifications are sent to ERCC.
The EFAS Informal Flood Notification is issued when a probability of exceeding critical flood thresholds are forecasted in a river basin where there is an EFAS partner but the forecasted event does not satisfy the rules of an EFAS Formal Flood Notification, e.g. warning lead time, size of river basin, or location of event. An EFAS Informal Flood Notification can also be issued if EFAS results are not conclusive but one of the multiple forecasts indicates risk of severe flooding.
Informal flood notifications are sent to ERCC.
Flash Flood Notifications
An EFAS Flash Flood Notification is issued when the probability of exceeding a 5 year return period magnitude of the surface runoff index is forecasted to be equal or greater than 10% and the forecasted start of the event is =< 48 hours in a region where there is an EFAS partner. EFAS Flash flood notifications are issued for administrative regions not for basins.
Flash flood notifications are sent to the ERCC