A massive power outage has left more than 1 million people in the dark in California, Arizona, and Mexico, reports AP. San Diego is especially hard hit. No definitive word yet on what triggered the problem about 4pm local time, but authorities made a point to rule out terrorism. "To my knowledge this is the first time we've lost an entire system," said an official with San Diego Gas & Electric. Temperatures were above 100 degrees in San Diego County at the time of the failure, which could mean a long, hot night for residents without air-conditioning. (More power outage stories.)