Letters emailed to Riordan High School families this week.

The San Francisco school is closing for at least two weeks after parents and a student tested positive for coronavirus. pic.twitter.com/8JZqDfuOZu — Kate Larsen (@KateABC7) March 11, 2020

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SAN FRANCISCO (KGO) -- The Archdiocese of San Francisco plans to close 90 of its schools this week because of several coronavirus cases.Riordan president, Andrew Currier, and a spokeswoman with the Archdiocese of San Francisco, both confirmed Tuesday night that a student at Riordan High School tested positive for COVID-19. It's the first juvenile case in the Bay Area and the second juvenile case in California.Because the student is a minor, public health officials can't release any information about his condition. The school is also unavailable to provide more specifics because of privacy reasons.There are also parents at Riordan who tested positive for COVID-19, which prompted a school closure and cleaning Monday, before the student's case was confirmed. It's unclear if the students and parents are related. Now a two week closure is in place for the school."We received messages from band that we had a two-hour window today to go through one door to retrieve any instruments that were left there, to bring back for the next two weeks so they could continue to practice," said Deidre Von Rock, whose son is a sophomore at Riordan.Von Rock says teachers plan to post classwork online, so students can keep up with their assignments during the two week closure.She says her son is feeling conflicted. "He's a teenagers so he's like yay, school is out. But also at the same time, these grades count, he doesn't want to get behind in anything, they're not really supposed to be socializing with friends, so it's just really a cause for concern."The superintendent of schools for the Archdiocese of San Francisco sent a letter to families Tuesday... explaining that "additional diagnoses of COVID-19 across our schools are likely" and that all classes and activities will be canceled from March 12th to March 25th.In all, 90 schools in the diocese will be closed, including four high schools: Riordan and Sacred Heart Cathedral Prep in San Francisco, Junipero Serra in San Mateo, and Marin Catholic in Greenbrae."Yeah, it's going to be a little challenging," said Matt Callahan, who has a daughter is a 7th grader at Saint Monica's in the Richmond District.Saint Monica's and most schools in the Diocese are in session Wednesday, so students can collect books and supplies from teachers."It seems they'll be doing their work at home and they've got to manage their day," said Callahan, who is working from home because of coronavirus concerns at his office, so at least he'll be around to supervise his daughter.