London, Ontario made the news when residents were treated to a rare sight on Monday, Aug. 12. During a heavy thunderstorm, a massive smoke ring appeared in the sky following a huge lightning strike.\nNancy Hutton from London Hydro told CBC News that lightning had hit a transformer somewhere on the east side of the city.\nNarcity spoke with London resident Kirstie Blake, who described her experience before seeing the smoke ring in the sky.\n"There was the loudest noise I’ve ever heard and all the lights went out," she said, adding that the power was only out for a few seconds. "I looked beside me out the window and noticed a huge cloud of smoke rising. I yelled to my boyfriend that there was an explosion of some sort."\nApril M. shared this eerie photo with us of what appears to be a smoke ring over London after a lightning strike hit...Posted by Ontario Tornado Watch / Ontario Blizzard Watch on Monday, August 12, 2019\nKirstie Blake\nHutton told CBC, "When a transformer is affected like that, it normally makes a 'boom.'"\nBlake described looking outside and seeing the ring forming. "I took as many photos as I could, and we both joked that it was a UFO," she said. "But I had seen the cloud of smoke just seconds earlier before it turned into a circle."\nThe smoke ring certainly did look otherworldly. However, despite all appearances, its origins were Earthly.\nKirstie Blake\nHutton could not confirm to CBC whether the smoke ring was caused by the exploding transformer, but she did note, "Sometimes there's fire. You might see sparks, you might see smoke."\nBlake said that the smoke ring hovered in the sky for about four minutes before dissipating completely. "I was scared at first not knowing what had happened," she said. "I thought either a house or tree got hit by lighting originally."\nAccording to Hutton, about 100 residential units were left without power until it was restored on the morning of Tuesday, Aug. 13.