HELSINKI—A powerful winter storm swept through northern Europe over the weekend, killing at least four people, destroying houses and cars, closing bridges, and causing flooding and halting transport while leaving thousands of households without electricity. Storm Malik was advancing in the Nordic region on Sunday, bringing strong gusts of wind, and extensive rain and snowfall in Denmark, Finland, Norway, and Sweden. Malik reached the Nordic region and northern Germany late Saturday after moving in from Britain where it caused havoc with material damage and transport chaos, hitting Scotland particularly bad. In the UK, a 9-year-old boy in Staffordshire, England, and a 60-year-old woman in Scotland were killed Saturday by falling trees as strong winds battered northern parts of Britain. Wind gusts of more than 100 mph (160 kph) have been reported in parts of Scotland, causing widespread disruption to transport and leaving tens of thousands of homes without power. Scottish …