The humming noise heard in the video below isn't new for long-time San Francisco residents. According to CBS, the high-pitched whistling can be heard for miles. It's only gotten worse since the city put in a handrail retrofit to make the span more aerodynamic on windy days.
Because the slants are more narrow, meaning air can flow more freely across the bridge. That also means the slants vibrate more and produce frequencies when strong winds pass through them.
“I couldn’t really describe the sound,” one San Francisco resident Brianne Howell told CBS. “I think I described it as wind chimes at first and, then, like when you blow into a beer bottle. But then, like multiple beer bottles, because it’s different tones.”
It may be an annoyance for nearby residents, but it sure makes for the perfect soundtrack on a stormy October day.
Jack & Carolyn talked about this on the Morning Breeze. Listen here: