by Eric Sprokkereef (RWS)

Figure 1 shows the number of formal, informal, and flash flood notifications issued each month throughout 2020. With a total number of 2213 EFAS notifications, the year 2020 outnumbers the previous record year 2019 by almost 50%. Consequently 2020 was by far the most active year for the EFAS consortium since the beginning of the operational service. Compared to 2019 EFAS DISS issued 37% more formal, 38% more informal and 50% more flash flood notifications. December was the most active month with 407 notifications, which is about 18% of the annual sum for 2020. May saw the highest number of formal notifications, whereas the period from July till September was relatively quiet in terms of flood notifications. In total 240 formal, 159 informal and 1814 flash flood notifications were issued in 2020.

Remarkable periods in 2020 were the last week of February with floods in the United Kingdom, the beginning of March with floods in France, the second and third week of May with large spread floods in the Pyrenees (France and Spain) and the period from the end of May till the beginning of June with snow melt driven floods in Finland, Norway and the Russian Federation. The month of December was characterized by intense precipitation, causing many flash flood notifications in Italy France, Spain, the British Islands and the Balkan Peninsula. 

For comparison, Figure 2 indicates the total number of EFAS notifications per year for the past 8 years. 2020 was again a record year for all types of notifications, but especially the increase in flash flood notifications was remarkable.

Figure 3 breaks down the number of notifications over the past 3 years into seasons (December-January-February [DJF], March-April-May [MAM], June-July-August [JJA] and September-October-November [SON]). 

The most active seasons in terms of river flooding over the past 3 years were all beaten by the year 2020. The reason for that is the amount of flash flood notifications that has been issued in all seasons of 2020. If you only look at formal and informal notifications, then the most active seasons were the winter of 2020, the spring of 2018, the summer of 2020 and the autumn of 2019.

Based on the number of notifications issued from 2018-2020, the most formal flood notifications are issued in spring (78 per year on average), the most informal flood notifications in winter (38 per year on average) and the most flash flood notifications in autumn (304 per year on average). The season with the lowest amount of formal notifications is summer (26 per year on average).
In 2020 in total 39 countries received 2213 notifications (240 formal, 159 informal and 1814 flash flood notifications). Spain received the highest number of notifications (45 formal, 17 informal and 261 flash flood notifications). The highest amount of formal notifications has also been sent to Spain (45), followed by France (29). The highest amount of informal notifications was sent to Austria and Spain (17) and the highest amount of flash flood notifications to Spain (261), followed by Italy (129) and Romania (114).

In 2020 EFAS DISS has started with the analysis of the results from the floodlist information system on an operational basis, using the Global Reporting Tool (GRT). Reported flood situations for large river basin throughout the world are analyzed once a week. Verified information is released for publication on the Global Disaster Alerting Coordination System (GDACS) that is used by the UN and the EU to coordinate disaster relief actions.
In total 630 flood reports have been verified and released for publication in GDACS by EFAS DISS in 2020. 136 events occurred in Africa, 286 in Asia, 51 in Europe, 62 in North America, 65 in South America and 30 in Australia and Oceania.