Heavy rains triggered flash floods in parts of western and central Germany, killing at least 106 people and causing property damage and transport disruption.

Flash flooding in Germany turned streams and streets into raging torrents that swept away cars and caused houses to collapse.

Hundreds of people are unaccounted for in Germany's worst-hit Rhineland-Palatinate state after the heaviest rainfall in a century caused deadly flash floods, the local officials said.

The village of Kordel in Trier-Saarburg, which has around 2,000 residents, has been completely cut off.

4,500 people in villages in North Rhine-Westphalia had to be evacuated. Westnetz, Germany's biggest power distribution grid, said on Thursday that 200,000 properties in the North Rhine-Westphalia and Rhineland-Palatinate regions were without power in Germany and that it would be impossible to repair substations until roads were cleared.

The Deutscher Wetterdienst, the German Meteorological Service, said that the quantity of rain in some areas of Germany was the highest for over 100 years.

In Stolberg, North Rhine-Westphalia, hundreds of people looted empty shops.

Search and rescue efforts were hampered by the fact that phone and internet connections were down in some parts of the county.

An emergency was declared in the region when heavy rains caused disruption in rail, road, and river transport.

In Belgium, all residents of Liège, the third-largest urban area in the country with a population of approximately 200,000, were urged to evacuate amidst fears that the River Meuse could burst its banks and that a dam bridge could collapse.

No vehicles were allowed into the city center of Liège, traffic was only allowed to leave as part of the evacuation. Several smaller municipalities in Limburg Province were also given the order to be evacuated.

In addition, due to the heavy flooding, several municipalities in Liège and Namur provinces were left without potable tap water.

Around 41,000 households were left without electricity in Wallonia. An empty passenger train was derailed at Grupont when the trackbed was washed out by floodwater. The Charleroi–Namur–Liège line, and all railway lines in Belgium southwest of that line, were closed. The overall damages to the rail network were estimated to take several weeks to repair.

Early estimations also pointed to severe damage to the country's agricultural sector, including long-term effects like soil erosion. During the flooding itself, farms and livestock had to be evacuated and many fields were damaged and crops destroyed by inundation.

The Circuit de Spa-Francorchamps suffered damage to access roads and its digital safety infrastructure. The circuit is due to hold the 2021 Belgian Grand Prix on 29 August.

Belgian Prime Minister Alexander De Croo declared 20 July a national day of mourning. (ILKHA)