The rainfall flooded the runway on Wednesday evening, leaving hundreds of passengers stranded on planes for several hours.

The storm dumped huge quantities of water and reportedly unleashed over 25,000 bolts of lightning in about an hour.

Videos posted on social media have shown that large parts of the runway were covered with water.

Ground handling at the airport had to be stopped altogether for more than two hours. More than 20 flights headed for Frankfurt were diverted to other airports.

The airport operator has said in a statement that the weather conditions will affect Thursday’s flight schedule and may cause further cancellations and delays.

“Passengers should check flight times with their respective airlines. Due to increased passenger volume, we advise all passengers to arrive at the airport 2.5 hours before their flight time,” the operator said.

There were more than 350 instances of water flooding into buildings and 17 fallen trees, they said, adding that off-duty personnel were called in to help.

The storm also affected other areas, with Gelsenkirchen, in the region North Rhine-Westphalia, hard hit.

Streets, cellars and lower-lying residential areas were rapidly flooded while trees toppled over, hitting vehicles, the fire service said.

Emergency service workers rescued people from vehicles at several highway underpasses.

In one area, parked vehicles became submerged, and some streets were only passable with inflatable boats.

Experts say that the climate crisis is increasing the frequency and severity of floods.

In 2021, Germany’s western regions of Rhineland-Palatinate and North Rhine-Westphalia were hit by catastrophic floods that killed over 180 people.