The tornado never touched down in San Francisco. But the conditions in the atmosphere with wind speed and direction were right, said Brian Garcia, warning coordination meteorologist for National Weather Service in the Bay Area. “San Francisco got lucky,” he said.

Powerful storms swept through parts of Northern California on Saturday, knocking down trees, causing widespread power outages and prompting weather officials to issue what they said was the first-ever tornado warning for San Francisco.

San Francisco residents were woken up by a tornado warning early Saturday morning during a powerful storm system that battered the region with heavy rain and wind.