Heavy winds that swept through the region downed dozens of power lines in Royal Oak while a generator to provide power at one house started a fire that destroyed the owner’s detached garage. Firefighters were called to Chippewa Street, off Woodward north of Normandy, after 5 p.m. Sunday. Royal Oak Assistant Fire Chief Jim Cook said a neighbor noticed the blaze and called the homeowner. “The winds were coming across at 40 mph and this thing was burning like a blow torch,” he said. “The (owner) ran a generator in the garage after losing power and the fire started about a half hour later.” Fire officials said the generator was propane fueled and connected to the house’s power circuit. The family at the house had left the overhead garage door open while the generator was operating. The garage was mostly burned down when firefighters arrived. The fire destroyed not only the garage but evidence that may have given investigators a better idea of how the blaze started.