BERLIN—Heavy summer storms caused widespread damage and flooding Tuesday in Germany and Switzerland, where an airport hangar partially collapsed in the southern town of Magadino. Swiss police said several planes were damaged but nobody was hurt when the hangar roof gave way amid heavy rain and strong winds overnight. Trees were blown onto roads and rail tracks in Zurich, causing travel chaos for commuters, while authorities warned that several rivers in Switzerland could burst their banks. Some Alpine passes were temporarily closed due to heavy snowfall. In neighboring Germany officials warned of “extreme storms” on Tuesday in the Eifel region southwest of Cologne due to particularly heavy rainfall. Persistent rain in recent days has swelled rivers and the Rhine is predicted to hit the first high-water mark on Thursday or Friday, triggering restrictions to shipping. The wet weather has been welcomed by some forestry officials in Germany after three particularly …