Fairfax County school administrators this week acknowledged “challenges” affecting the learning environment at Fort Hunt Elementary, a school that has experienced high teacher turnover amid parent and teacher complaints of low morale.

In letters to families and faculty at the start of the school year this week, Fort Hunt Principal Barbara Leibbrandt and her immediate supervisor, assistant superintendent Deborah Tyler, wrote that they are committed to the school, in the Alexandria section of the county. Both declined to comment for a Washington Post article about the school that described parent and teacher concerns about a “toxic” environment there.

“We have a great school,” Leibbrandt wrote. “Yes, we do have challenges, but together we will address them.”

In a recent employee survey, Fort Hunt ranked second-to-last among county elementary schools. Bull Run Elementary in Centreville ranked at the bottom of Fairfax County’s 139 elementary schools.

Parents and teachers told The Post that the school’s environment was negatively affecting the lives of students. This year, about 40 percent of the instructional staff left Fort Hunt — double the overall rate for its cluster of county schools — and leaders of a teachers’ organization representing Fort Hunt staff members reported complaints about record-low morale.

Leibbrandt wrote in her letter that Fort Hunt teachers left “for a variety of reasons,” including for a job with a shorter commute and promotions. She also wrote that “yes, some teachers left because they feel their teaching approach or philosophy does not match those established for Fort Hunt Elementary.”

Leibbrandt did not return a call seeking comment Wednesday.

In her letter, Tyler reaffirmed her support for Fort Hunt students and the new and remaining staff members.

“Each child at Fort Hunt Elementary School deserves our unwavering collective effort as the adults who will serve as examples to set a limitless course for their future,” Tyler wrote. “I urge you to continue communicating with me as we work together to support this school.”

On the first day of school Tuesday, numerous parents gathered in front of Fort Hunt to talk about their concerns. One mother, whose children attend second and third grade, said the feeling of mistrust there had kept some families from voicing their opinions. But Tuesday the mood had changed, she said, and parents were openly discussing the matter.

One mother of sixth-graders, who, like other parents, spoke on the condition of anonymity to protect her children, dropped her kids off at the school and was surprised by how many new teachers there were. In all, the school hired an additional 21 teachers to replace those who left.

Another parent said he decided to remove his daughter from Fort Hunt in June 2012 amid concerns about the school’s climate. He said one example was when “crazy hair day” — when students and teachers would wear their hair in a wacky fashion or don colorful wigs — was canceled.

“An elementary school should be a fun place that encourages learning and encourage kids to want to go to school,” he said. His daughter now attends private school. “I complained, saying: ‘Isn’t it obvious what’s going on? Why is there so much turnover?’ ”

Tyler, the assistant superintendent, wrote in her letter that challenges can create opportunities for a positive outcome.

“This is our opportunity to continue addressing these challenges with solutions that will be dependent upon continued dialogue,” Tyler wrote. “Our charge for this school year shall be joining together in a supportive manner to move beyond these recent events.”