Three were killed in Dusseldorf when a tree fell on a garden shed where they waited out the storm, and three others in the shed were injured, two seriously. Bicyclists were killed by falling trees in Cologne and in Krefeld, and another person died while clearing an Essen street, emergency service personnel said.
"We must reckon that the total damage will run into double-digit millions," North Rhine-Westphalia Interior Minister Ralf Jaeger said. "That was one of the worst storms to hit (the region) in the past 20 years."
Winds of up to 150 kilometers per hour (93 mph) were recorded at Dusseldorf's airport, following record-breaking temperatures of 38 degrees Celsius (97 degrees Fahrenheit). Authorities urged commuters to avoid the city's roads, train stations and airports; meanwhile, power lines in Dusseldorf were damaged. Its urban tram system was suspended as well.