San Francisco Downtown Faces its First Tornado Warning in History

On Saturday, December 14th, the city center of San Francisco, California issued its first-ever tornado warning, as strong winds swept through the city, causing trees to fall and widespread power outages.

In the early morning hours on Saturday, over 1 million residents in San Francisco and its outskirts were startled awake by mobile alerts, urging them to “evacuate immediately.” The San Francisco Department of Emergency Management (SFDEM) confirmed that the tornado threat ended around 6:14 AM Pacific Standard Time, with the storm moving towards the northeast of the city center.

The warning was specifically issued for the northern part of San Mateo County and certain areas in downtown San Francisco.

In earlier tweets, SFDEM urged San Francisco residents to “seek shelter now inside a basement or the lowest floor of a sturdy building. If you are outdoors, in a mobile home, home, or vehicle, move to the closest sturdy shelter and protect yourself from flying debris.”

The National Weather Service (NWS) also issued flood warnings and high wind alerts, predicting sustained coastal wind speeds of up to 40 miles per hour. San Francisco Airport reported gusts of up to 72 knots (83 miles per hour) as the storm passed through. Videos showed strong winds shaking palm trees in San Francisco, toppling trees and power lines.

As of Saturday morning, over 10,000 households in San Francisco were without power. According to the PowerOutage website, the storm led to more than 221,000 households in Northern and Central California losing power.

The NWS Bay Area Forecast Office warned local residents to stay away from the coast during the weekend as coastal flood warnings would remain in effect until Monday.

California experiences an average of 9 tornadoes annually. The National Weather Service confirmed that downtown San Francisco had never before received a tornado warning.

Meteorologist Roger Glass from the National Weather Service told the Associated Press that the last tornado to hit San Francisco was in 2005, but that storm did not show any significant radar signals, so no warning was issued at that time.

Just a week prior on December 5th, a 7.0 magnitude earthquake struck the California coast, leading to tsunami warnings for nearly 5 million people in the San Francisco Bay Area, Northern California, and parts of the Oregon coast. Such a strong earthquake is relatively rare, with official reports stating that globally there are only about 15 occurrences per year.

(This article references reports from CNN and BBC)