A shelter-in-place order was issued Tuesday afternoon after at least one large glass panel "became separated" from the 43rd floor of famed SF office tower 555 California Street, formerly known as Bank of America Center.

The San Francisco Fire Department blocked off California Street and other streets in the vicinity of the 52-story tower, and they were telling workers inside the building to remain inside as well.

SFFD Captain and Public Information Officer Jonathan Baxter said in an announcement that firefighters would be going "door to door" in the tower to help people inside get out safely.

Baxter said that the SFFD, SFPD, Muni, and other public safety agencies were "working collectively to mitigate this incident."

"This is still an active scene with an active hazard," Capt. Baxter said. "Please avoid the area."

NBC Bay Area reporter Sergio Quintana reported from the scene that one glass panel had come loose on the Kearny Street side of the building, and firefighters were concerned about a second panel coming loose on the California Street side.

Update: Here is a video from early on in the incident, showing pieces of glass tumbling to the street.

The entire Bay Area remains under a high-wind advisory, and gusts of around 80 miles per hour caused delays and a full ground stop at SFO today.

A similar situation occurred in early January when stormy weather took out a glass panel on Fox Plaza, near Civic Center.

We'll update you if we learn more.