In a stunning move, the Cupertino Union School District announced late Wednesday night that all 24 teachers at West Valley Elementary School will be reassigned to other district campuses.

As a result, the high-performing Sunnyvale school will open in the fall with an entirely new roster of teachers as well as a new principal.

The district and the Cupertino Education Association agreed Wednesday evening to start with a fresh slate at West Valley, which by the district superintendent’s own admission was rife with tension for a long time.

West Valley teachers were alerted via email Wednesday night of the decision; included in the message was an attachment of a memorandum of understanding jointly crafted by the district and union.

The latest development came as a surprise to teachers and parents, who had been told at a community meeting Monday that West Valley teachers would have to reapply for their jobs; they weren’t told that the teachers would necessarily be sent to other schools.

Union president Dave Villafana said the decision to reassign everyone at West Valley stemmed from a desire to protect teachers from feeling singled out if moved elsewhere.

“We were looking at a fair process of how you would elect the teachers that would stay (at West Valley) and the teachers that would leave,” he said. “The fair process would be to move everybody and we agreed with that.”

The Cupertino Education Association would not have been involved in the rehiring process but wanted to avoid any fairness or perception issues.

“[Teachers would be asking], ‘why did I get moved and somebody else didn’t? And what criteria did you use?’ ” Villafana said. “We’re trying to protect all the teachers when it comes to that.”

The memorandum asks West Valley teachers to indicate the schools and grade levels they prefer for the upcoming school year, which begins in August.

It also states that special education resource specialists, speech language pathologists, psychologists, nurses, fourth- and fifth-grade physical education teachers and music teachers are exempt from relocation.

It remains unclear what specific event or series of events at the school resulted in the apparent turmoil. The district, citing legal reasons, said it won’t release details about individual personnel or specific incidents.

But on Thursday, Superintendent Wendy Gudalewicz sent out a letter to school parents elaborating on some of the issues that sparked the dramatic changes.

“There has been a great deal of tension at West Valley among and between teachers, support staff, parents, and administration,” Gudalewicz states in the letter. “If you and your family did not experience or were unaware of this tension–that’s a good thing.”

Gudalewicz adds that the group dynamic at West Valley created “a culture that was not serving educational needs” and that the district’s decision to break up the faculty was “not taken lightly.”

The letter confirms that a number of measures were taken to try to deal with issues that appear to have been simmering even before this school year.

“Multiple interventions took place throughout the year,” Gudalewicz states in the letter. “A new principal was put in place at the beginning of the year. District level union leadership talked with staff. An all-day session with a facilitator took place at the end of the year to access the school climate. At this meeting it became clear that progress was minimal and internal change seemed unlikely.”

Teachers were first alerted to the campus shakeup the last day of school June 11 when teachers were informed by district administrators during a staff meeting that they would have to reapply for their current jobs.

A Monday meeting with the community was held at Cupertino Middle School to inform parents of the campus issues and introduce the school’s new principal. After one year as principal at West Valley and as an employee of Cupertino Union, Theresa Johnson was offered the vacant position of district coordinator of instruction. She accepted and will help implement English Language Arts curriculum across the district, according to the district.

Robin Robinson, who was Eaton Elementary School’s principal, will take the helm at West Valley. She was introduced to parents and teachers at Monday’s meeting. She comes to the school with 24 years of experience in education, 16 of those in administration. Robinson was approached about the possibility of taking over West Valley several days before June 11, according to the district.

New criteria for West Valley teachers have also been established by district administrators. Teachers and staff support should demonstrate a commitment and willingness to learn and grow, build and support a positive culture of learning and growth for all and develop a school community culture that practices empathy and caring for all stakeholders.

Gudalewicz also said at the Monday meeting that the goal is to create a “positive environment moving forward” and to “reinvent” the school. She stressed that the issues at West Valley had nothing to do with student performance.

According to Villafana, the process of relocating and placing new teachers could take a month, but West Valley is expected to be re-staffed by June 30.

Though Villafana said other teachers in the district will not be forced to relocate to West Valley, there will be a “domino effect” once West Valley teachers start moving to other campuses.