The Osher Marin Jewish Community Center in San Rafael and the Ronald C. Wornick Jewish Day School in Foster City were evacuated on Jan. 18 after receiving a bomb threat. 27 Jewish institutions in 17 states across the U.S. to received similar threats on that day.

The Marin JCC was cleared by mid-morning to resume normal operations by Marin County sheriff’s deputies, though its preschool remained closed for the rest of the day. Activities resumed before noon at the JCC’s fitness center.

Everyone from preschoolers to gym patrons was evacuated after the threat was received shortly before 9 a.m. Because of the rain, they were sent across the street to Venetia Valley Elementary School.

“We were able to bring the children and everybody that was evacuated into classrooms and the gym, and everyone was kept warm and dry,” said Iris Lax, the JCC’s director of marketing and strategic projects. “We’re very relieved this was just a hoax, but we help so many people in our community, and this upset us because it interrupted our ability to serve them.”

The Wornick School was evacuated by 9 a.m. “We started dismissing kids to go home at close to 10,” Head of School Barbara Gereboff told J.

The students and staff were evacuated to a nearby facility run by the city of Foster City. “We have emergency plans, and we already have meetings with police department when we talk about emergency issues, so we know them,” she said.

All the threats — which came a week after similar bomb scares were called in to 16 JCCs in nine states — turned out to be fake, officials said.

“In the wake of last week’s calls, JCCs were well prepared for the calls received today,” said David Posner, director of strategic performance at JCC Association of North America, who helps advise local JCCs on security policies and practices.

“Lessons learned and best practices discussed were clearly on display this morning, and we applaud our JCCs for responding calmly and efficiently. Many JCCs not affected last week took the opportunity to review their own security plans, and speak with local law enforcement.

“While we’re extremely proud of our JCCs for professionally handling yet another threatening situation, we are concerned about the anti-Semitism behind these threats,” Posner said. “While the bombs in question are hoaxes, the calls are not.”