Tens of thousands of music fans from Germany and many other countries gathered for the “Rock im Park” festival in Nuremberg and its sister event, the “Rock am Ring” at western Germany’s car racing track, the Nürburgring, on Friday.

Rain boots and shorts were the uniform for this year’s events, marred by constant rain and thunderstorm warnings in most of Germany. Around 45,000 fans braved the rain to rock with superstars in the inaugural concert at “Rock am Ring.”

The scene around Mendig, where the Nürburgring is located, was a muddy one. Police cordoned off several parking places near the festival venue because of swampy conditions. Meteorologists said temperatures in both locations would be around 22 to 25 degrees Celsius, with a high risk of storms. In 2015, 33 Rock am Ring visitors were injured by lightning.

Last week, the famed 24-hour Nürburgring car race was delayed for several hours because of stormy weather.

“The decisive question is, where a storm will actually occur,” weather expert Christian Herold told reporters. “It could actually bypass the festivals,” he added.

Around 80 bands are expected to participate in Germany’s twin festivals this year. Highlights include concerts with Ozzy Osbourne and his Black Sabbath, which is on its farewell tour, called “The End.” US bands Red Hot Chili Peppers, Korn and German band Fettes Brot are also expected to make an appearance.

mg/jr (Reuters, dpa)