Update: This story has been updated to reflect that Park County teachers are now on strike.

Teachers in the Park County school district are on strike Monday after negotiations with the district failed to yield an agreement.

This is the third teacher strike in Colorado in less than 18 months. This is the latest in a wave of teacher activism that has swept the nation and also has Chicago teachers on the verge of walking off the job.

On Friday afternoon, district and union representatives were exchanging emails to see if any meetings might occur over the weekend, but by Sunday, no meetings had occurred and teachers announced their intention to start picketing at 7 a.m. Monday.

Late Sunday evening, the district announced that classes would be canceled Monday, as would extracurricular and athletic activities.

Doug Freeman, a fourth-grade teacher and member of the union negotiating team, said teachers in the district, which serves roughly 600 students in the high valley of South Park, are sorry that a deal wasn’t reached earlier but feel the strike is necessary.

“Everybody is upset that we’re going to picket,” he said Sunday. “We want to be in the classroom with our students. We understand there is a long-term, bigger issue. It’s going to affect our future and our student’s future. The mood is very positive. We don’t want to do this, but it’s a necessity.”

District and union representatives met Wednesday and Thursday, the first formal talks since Aug. 23. Both sides characterized Wednesday’s meeting, which focused on various aspects of the contract or professional agreement, as productive. On Thursday, union members pushed to return to the question of salaries, which the district does not want to debate. And that’s where things ended.

The union has worked out an agreement with the local Boys and Girls Club to care for children whose parents don’t want to send them to school during the strike and collected food donations to provide meals. Teachers plan to rotate between the picket line and the Boys and Girls Club. The state teachers union, the Colorado Education Association, is collecting money for a strike fund.

The union received legal clearance to strike from the state Department of Labor and Employment in late September and set an official strike date of Oct. 14 earlier this week.

Freeman said the district’s roughly 40 teachers are willing to strike for better salaries, which union members believe is key to retaining educators and ultimately will benefit students.

“This is really not about a raise this year or next year,” he said on Friday. “It’s about making our compensation attractive so that teachers who are here don’t leave for other districts that pay more, and if we have an opening, teachers want to come here.”

The school board approved raises in May that amount to an average 6.5% increase, but union representatives say those raises aren’t enough to keep the district competitive and did not benefit all teachers equally. The average teacher salary in Park County is a little less than $41,000, on the low end for salaries in the same administrative area and 30% less than salaries in neighboring Summit County, home to affluent ski resort communities.

The previous contract or professional agreement in the Park County Re-2 district, which expired in the summer, had not allowed for collective bargaining over salaries. Changing that has been a top priority for the union, and two sides agreed this week to recognize the South Park Education Association as the sole bargaining unit for its members and laid out a mediation process for discussing salaries in the future.

The district said the sole remaining substantive issue was the length or term of the professional agreement and described the union as walking away from a deal.

“Although the association has been aware for months that the district would not be negotiating salaries prior to the reinstatement of an agreement, the association unilaterally inserted this topic into the agreed-upon dialogue for this week’s meetings and chose to walk away from the productive conversations with the district last night,” district officials said in a press release.

In a press release, union President Taya Mastrobuono described the disagreement like this: “The district team shut down our voice when we wanted to talk about our concerns on how we pay our rent and buy our groceries and gas, just as they have shut down that talk so many times before.”

School board President Kim Bundgaard has said higher raises are not fiscally prudent right now.

Freeman said compensation is a key part of the professional agreement, not a separate item, and teachers would lose important leverage if they don’t deal with both issues at the same time.

“If we do sign the professional agreement — and the district knows this — our South Park Education Association loses the ability to strike,” he said. “And that’s the power we have currently.”

A spokeswoman for the Department of Labor and Employment said officials could not comment on that statement because they haven’t reviewed the agreement because neither party has asked the state to intervene.

In the meantime, the union’s right to strike remains current until this dispute is resolved.