Mysterious Loud Boom in San Francisco Sparks Alarm Among Residents

A loud boom in downtown San Francisco on Monday afternoon caused alarm among residents, with many fearing an explosion. Initial reports suggest the noise may have been fireworks, but the San Francisco Police Department has not confirmed this. Social media was filled with reactions from locals who described the sound as powerful enough to shake buildings. Fire engines responded to the scene, but authorities have yet to provide further information on the incident. The exact cause of the noise remains unclear, leaving residents curious and concerned.

By Narendra Chaudhary Jul 21, 2026, 05:05 IST

Residents React to Mysterious Noise

On Monday afternoon, a sudden loud noise echoed through downtown San Francisco, leading to widespread concern among locals. Many initially speculated that an explosion had occurred near the 24 Hour Fitness located on Montgomery Street. However, as of that afternoon, the San Francisco Police Department had not verified any explosion.

Reports from the Citizen app, which alerts users to emergencies, suggested that the noise might have originated from fireworks, which some residents misinterpreted as an explosion. Social media was abuzz with comments from individuals who reported hearing the loud sound, with some stating it was strong enough to rattle nearby buildings. One user on X questioned, "Did someone just set off an explosion in SF?" while another expressed curiosity about the details of the loud noise.

Fire engines were seen responding to the scene, adding to the atmosphere of concern. Montgomery Street serves as a key route through San Francisco's Financial District, situated in the heart of the downtown area. As of now, authorities have not provided additional details, and the precise source of the loud noise remains unconfirmed.