Yellow rain alert brought heavy showers to Wallonia and Brussels

Updated 23 August 2026, 12:00 CEST — BRUSSELS — Belgium’s yellow rain warning expired late on Wednesday, 19 August, after the Royal Meteorological Institute (IRM) placed Brussels, every Walloon province and Flemish Brabant under heightened vigilance for heavy rainfall. The alert took effect at noon and ended by midnight, with the precise closing time varying slightly by area, according to L’Avenir and BX1.

The IRM warned that abundant rain could produce local water damage and traffic disruption in vulnerable areas. Its published criteria define a yellow rain warning as forecast rainfall of 20 to 30 litres per square metre in one hour, 20 to 40 litres over six hours, or 25 to 50 litres over 24 hours. A yellow code means vigilance is required; it does not by itself confirm that flooding will occur everywhere inside the warned provinces.

The federal Interior Ministry activated the 1722 service because of the warning, BX1 reported, citing the ministry. Residents needing firefighters for non-life-threatening storm or water damage were directed to the online portal at 1722.be or the 1722 telephone line. The ministry reserved 112 for situations involving an immediate threat to life.

A Walloon government assessment published on 20 August subsequently recorded substantial but uneven rainfall from the wider episode spanning 17 to 19 August. The regional authorities measured roughly 10 to 25 millimetres in southern Wallonia, 25 to 50 millimetres in the centre and 20 to 25 millimetres in the north-west. The same assessment confirmed that the IRM had issued a yellow rain warning on 19 August.

The rainfall arrived after a dry, sunny and hot period that lasted until Sunday, 16 August, according to the Walloon government. It offered some short-term relief but did not automatically end the underlying water concerns. Brussels Environment had already said on 18 August that expected rain would not be sufficient to normalise the capital’s drought indicators and retained a separate yellow drought-vigilance level.

The episode illustrates why weather alerts and drought monitoring can coexist: one tracks an immediate risk from intense rainfall, while the other reflects water availability over a much longer period. The warning has now ended. Residents should consult the IRM for new forecasts and regional hydrological services for subsequent river-level information; no consolidated official damage total from the 19 August episode was identified at the time of this update.