As UC Berkeley lurches into the final four weeks of a spring semester upended by the coronavirus pandemic, another quandary looms on the not-so-distant horizon: fall semester.

School officials have not yet made a decision about the fall, but students and faculty are bracing for online instruction extending into the new academic year. That would allow for social distancing but raise a variety of other issues.

The financial stakes are high. Chancellor Carol Christ, in an email Friday to faculty and staff, estimated the budget impact of COVID-19 on the school “in the range of $200 million,” thanks to a combination of lost revenue and increased expenses.

“It has become clear we will need to continue to invest in remote learning,” she wrote in the email, “and provide the necessary resources for employees to be able to effectively work remotely.”

Christ, in another email April 1, detailed the many ways in which UC Berkeley is losing revenue, from the premature end of housing and dining contracts to the absence of intercollegiate athletics. She also noted an “uncertain enrollment picture” for the fall semester, especially involving out-of-state and international students who pay the highest tuition.

Cal and Stanford, like most colleges and universities across the country, charged full tuition for the spring term despite moving to online classes in mid-March. Students at Drexel, the University of Miami and Arizona’s public universities have responded by suing to seek a reduction in costs.

Online classes will continue at Bay Area schools through the summer session. But fall plans are spinning in doubt, as campus leaders try to balance public health concerns and a profound economic crunch.

That’s one reason Panos Papadopoulos, a longtime mechanical engineering professor at Cal and former chair of the Academic Senate, expects school officials to try to implement a “hybrid system” for the fall semester. In this scenario, large-enrollment lecture courses would be taught online and smaller courses, lab sessions and discussion sections would take place in person, while following social-distancing guidelines.

“The logistics of such a hybrid approach are very complex,” Papadopoulos said in an interview with The Chronicle. “However, the alternative of a fully online fall semester would substantially diminish the instructional experience and would also be financially catastrophic for the campus.”

Much could change before fall classes begin in four-plus months — on Aug. 26 — as Papadopoulos acknowledged, including potential intervention from Gov. Gavin Newsom. And a hybrid system brings abundant challenges: It may not work well for some courses, may be a disadvantage to some students and ultimately may not be as effective as traditional, in-person instruction.

Plus a mix of online and in-person classes probably would force UC Berkeley to reduce tuition to some extent.

“It’s complicated for the school, because you have to do two types of planning simultaneously,” Papadopoulos said. “There are issues with classrooms, because we don’t have enough large classrooms to spread the students.”

Asked if such a hybrid plan could work, he replied, “I think it can. Look, it has to work. It will not be perfect, but it will work.”

Christ and other top UC Berkeley officials are contemplating their options for the fall semester and recently formed a work group to explore the matter, according to campus spokeswoman Janet Gilmore. She said the group is just starting its work and it’s “too soon to speculate” about fall plans.

Still, student leaders realize a full semester of online instruction is distinctly possible. Aastha Jha, academic affairs vice president for the Associated Students of the University of California, has been involved in discussions about the fall semester and shares Christ’s concern about a potential drop in enrollment and the ensuing economic impact.

“Many students could choose to stay home until things have calmed down in the world,” Jha said.

Or, as lecturer Crystal Chang Cohen said, “My personal view is that another semester of remote learning is very likely, given the fact students, staff and instructors alike will be wary of returning to campus without a treatment or vaccine for the virus.”

The repercussions would stretch beyond precarious campus finances. Consider students such as Maja Ahmann, a junior who expects to graduate in December with majors in legal studies and public policy.

She’s completing the current spring semester at her family’s home in Lincoln, Neb. And if online classes extend into the fall, she absolutely expects a break on her hefty out-of-state tuition.

“I would be very upset if my final semester at Cal was online,” Ahmann said. “My education has changed this spring — I’ve lost a lot of the perks of being on a college campus, like no access to libraries or office hours.”

Other schools in the Bay Area are grappling with the same issues. Stanford, USF, San Francisco State and San Jose State all will hold summer sessions online, and none of the schools has finalized plans for the fall, according to school spokespeople. St. Mary’s College, with an average class size of 20 students, is planning in-person fall classes “at this time,” a school spokesman said.

As for Berkeley and the other nine UC campuses, they will take guidance from systemwide headquarters, and then campus leaders will decide how to conduct business in the fall.

“Our campuses will reopen for on-site instruction when it is safe to do so,” UC spokesman Andrew Gordon said.

Ron Kroichick is a San Francisco Chronicle staff writer. Email: rkroichick@sfchronicle.com Twitter: @ronkroichick