A thunderstorm that swept through large parts of Germany on Monday night left as many as six people dead and 30 seriously injured as a holiday marking the feast of the Pentecost ended in tragedy.

A 28-year-old cyclist from the northern town of Krefeld was electrocuted after a falling tree hit power cables in his path, according to a police statement. Three people died after a tree fell on a summer house in Dusseldorf. A 52-year-old cyclist in Cologne suffered a similar fate as the storm left a trail of destruction across North Rhine-Westphalia, Germany’s most- populous state. A sixth person died in the city of Essen while attempting to clear damage, according to Der Spiegel.

Thunder and lightning struck after temperatures reached 35.6 Celsius (96.08 Fahrenheit) in the southern town of Waghaeusl, the highest recorded in Germany for the first 10 days of June, according to the DWD national weather service.

Rail traffic across the state was severely disrupted with services between Cologne and Dortmund grinding to a halt, according to Deutsche Bahn AG. Vehicle traffic is also hampered with total damage from the storm estimated at “millions of euros,” a police spokesman said by phone from Duisburg.

“Heat records were falling like dominos yesterday,” Christoph Hartmann, a meteorologist at Offenbach-based DWD, said in a statement. Severe weather warnings remain in place with temperatures forecast to rise to more than 33 degrees [91.4F] and wind speeds expected to reach levels typical for hurricanes, according to the weather service.

–With assistance from Julia Mengewein in Frankfurt.