This page is a repository of known issues of the European Flood Awareness System (EFAS). Please keep these in mind when using EFAS and related data.

Known issues include, but are not limited to, forecast issues, production incidents, and data quality deterioration.

EFAS is an operational system so it is important we are made aware of issues/errors in our system in a timely manner. If you find a problem or any feature missing that you think should be present, and it is not listed here, please let us know by reporting it through the ECMWF Support Portal, mentioning "EFAS" in the summary.







Erroneous EFAS v5 data and products from launch (on 2023-09-20).

Erroneous EFAS v5 historical simulations from 2023-01-01. 

A bug was identified introducing errors in the initial conditions of all EFAS v5 forecasts since its operational launch on 20 September 2023. The error also impacted all reforecasts and the historical simulation from 01 January 2023.

What to do: Previously downloaded data should be disregarded and users should download the data again.

EFAS-historical: Due to an error found in the calculation of the initial conditions users who downloaded EFAS version 5 data between 19 September 2023 and 29 May 2024 are advised to redownload the data. 

EFAS-forecast: Due to an error found in the calculation of the initial conditions of EFAS version 5, EFAS forecasts are not available from 20 September 2023 onwards.

EFAS-seasonal: Due to an error found in the calculation of the initial conditions of EFAS version 5, EFAS seasonal forecasts are not available from October 2023 onwards.

EFAS-seasonal-reforecasts: Due to an error found in the calculation of the initial conditions of EFAS version 5, EFAS seasonal reforecasts are only available up until December 2022. 



Incorrect NetCDF data provided for EFAS datasets on the CDS

EFAS data downloaded from the CDS in NetCDF format are incorrect between Tuesday, March 19th and Thursday, March 21st, 2024 only. See this forum post for details.

What to do: Download the data again.



Post-processed forecasts not available from SOS

Some technical issues are impacting the SOS data server with no EFAS5 forecasts available. 

The impact is only a dissemination issue and does not affect the post-processed forecasts shown on the EFAS-IS mapviewer nor any other dataset



Incorrect timestamp for EFAS v5.0 historical data

Affected dataset: 

It has been determined that an error was made when archiving the pre-release EFAS v5.0 historical data to MARS. This error has now been corrected.

The impact of this was that the discharge data was shifted in time by 6 hours.

Usually, discharge data retrieved for the 12:00 timestep represents average discharge over the following 6 hours (i.e. from 12:00 to 18:00). This is because, in MARS, data is archived at the beginning of the timestep.

However, the error in archival means v5.0 historical data for the 12:00 timestep represented data over the previous 6 hours (i.e. from 06:00 - 12:00). 

This error is now corrected and the data has been rearchived correctly in MARS. The v5.0 pre-release data was removed from the CDS temporarily while this was fixed.



SYNOP layer inaccurate 

A technical issue linked with the processing of SYNOP data at ECMWF has impacted the quality of the SYNOP layer shown on EFAS. This does not have any impact on the EFAS service which does not use the data stream used in the SYNOP layer.

To avoid any confusion, the SYNOP layer has been disabled on EFAS-IS



Social Media Activity Analysis layers unavailable on EFAS-IS

Affected layers:

  • Social Media Activity Analysis
  • Social Media Activity Analysis - Tweets


ongoingErroneous data served when using the CDS sub-region extraction tool

An issue has been identified with the EFAS sub-region extraction tool, whereby it serves data that is not correctly located on the river network. Any time-varying data (i.e. River discharge in the last 6 or 24 hours, snow depth water equivalent, and volumetric soil moisture) that has been downloaded using this tool from 2018 until now is not located at the correct position on the network when compared to the upstream area.

The sub-region extraction tool has therefore been removed from the EFAS CDS entries for versions up to v4, and any area specified in cdsapi requests will return the entire domain .

Data previously downloaded using this tool should be disregarded.



EFAS forecasts degraded over Ukraine

Erroneous precipitation values were reported on 09/03/2022, and brought about high accumulations of snow and its forecasted melting, in the EFAS system. EFAS technical contacts in Ukraine were made aware of this degradation in the forecasts.

Due to the ongoing situation in Ukraine, the quality of EFAS results for the region had been lowered due to lack of national precipitation data. The EFAS team found a solution to replace missing precipitation observations with data from ICON. Solar radiation was also affected and infilled by ICON data, but was switched back to observations on  



EFAS short and medium-range forecasts degraded

EFAS historical degraded

EFAS forecast quality may be degraded until further notice due to missing meteorological observations caused by an IT security incident at the Meteorological Data Collection Center



all EFAS forecasts degraded

EFAS historical degraded

Partial meteorological observations received to initialise EFAS forecasts caused by the maintenance of the JRC MARS database

*most recent issues are listed at the top of the table