A freak windstorm swept across Europe this week, uprooting trees and cutting power to millions of people. At least 30 people were killed, most of them by falling trees or flying roofs. In Germany, cars flipped over in the streets and telephone poles toppled onto houses. In the Netherlands, 120 mph winds lifted an elderly man several feet in the air and slammed him into a fence, killing him. The storm, Europes gustiest in a decade, also killed people in France, Britain, Austria, Belgium, Denmark, Poland, and Switzerland.