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City to shut down siren system for two years

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Tuesdays at noon just won’t be the same

A cluster of white siren horns. Photo by Shutterstock

Grab a black veil and say a little prayer. The Tuesday noon siren in San Francisco will cease its weekly blaring for two years after December 10 for systemwide upgrades.

How does the siren system work?

The Outdoor Public Warning System (OPWS), as it’s known, is a citywide system of 119 sirens that alerts denizens about life-threatening issues like an earthquake, a tsunami, contaminated water supply, or a nuclear attack.

The city tests the system each Tuesday at noon. In the event of an actual emergency, a 15-second tone will sound repeatedly for five minutes with audible instructions.

The last non-testing, real-life use of the system, according to the Department of Energy Management (DEM), “was on Treasure Island in 2012 due to potential water contamination on the island caused by a water main break.”

Why is it being repaired?

It’s antiquated. San Francisco will invest between $2,000,000 to $2,500,000 in upgrades to the bring the OPWS up to snuff. Upgrades will include new hardware that will improve the reliability system. These updated will take two years, it seems.

The last major upgrade of OPWS was in 2005.

Will the siren sound different?

No, the siren will sound the name when it runs again in 2021.

Why will it take so long?

“Special equipment needs to ordered,” says the DEM. And installation and testing to all 119 sirens takes time.

What others resources can I use to be notified in case of a disaster or emergency?

There are several ways to receive emergency notifications, alerts, and warnings.

  • AlertSF: an emergency text message system that sends mobile subscribers messages and instructions following a natural disaster, major police presence, fire, or bonkers transportation disruptions. To subscribe, text your zip code to 888-777 or visit to register to receive alerts.
  • @SF_Emergency: The official profile for the San Francisco Department of Emergency Management that tweets our emergency information.
  • Emergency Alert System: The loud piercing warning you hear via broadcast, cable, satellite communications. You’ve seen or heard these warnings on the television or radio.
  • Wireless Emergency Alerts (WEA): According to the DEM, “Wireless Emergency Alerts (WEAs) are used to send concise, text-like messages to WEA-capable mobile devices during emergency situations. WEAs are sent by your state and local public safety officials, the National Weather Service, the National Center for Missing and Exploited Children, and the President of the United States. Most people recognize WEA as the Amber Alerts they may receive on their phone.”
Has @SFSiren, the unofficial Twitter account of the siren system, made a statement?

Not yet. But Curbed SF will keep abreast of the situation.