outages caused by Mylar balloons that get tangled up in power lines. These colorful, helium-filled metallic balloons often are given as gifts to celebrate these special occasions, but if they are accidentally let go into the air, they can cause power outages that can last for a few minutes to hours.
https://www.edison.com/content/dam/eix/documents/newsroom/news-releases/053013_news1.pdf

