A family feud may result in the sale and liquidation of Portland's iconic Alpenrose Dairy, according to a new lawsuit filed by the great-great grandchildren of Florian Cadonau, who started the family dairy in 1891.

The three siblings behind the $35 million complaint claim their two aunts plan to close a sale "in a matter of weeks" to a third-party buyer that would immediately end community events at the farm and shut down the dairy within two years.

Alpenrose became an official business in 1916, when Cadonau's children took over operations. In 1961, Alpenrose held its first annual iteration of the popular holiday event Christmas in Storyville at its Southwest Portland property. Today, the farm hosts the Alpenrose Challenge, a bike race on the farm's notoriously steep velodrome track, and is home to local softball teams and a 4-H farm. It also employs more than 150 people.

Six generations of family business culminated in the Cadonau Legacy Plan—corporate governance documents intended to preserve the business, its numerous community events and its significance as a part of living Portland history.

But part of the family wants to scrap that plan and cash in, according to a lawsuit filed Monday in Multnomah County Circuit Court.

The historic dairy and its events "are in imminent threat of being extinguished," the lawsuit says. It blames two family members, Barbara Deeming and Anita Cadonau-Huseby, who "are committed to liquidating Alpenrose."

The lawsuit was filed by siblings Carl Cadonau III, Tracey Cadonau McKinnon and Cary Cadonau. The three siblings are suing their two aunts. They claim their grandfather Carl Cadonau Sr., who was the father of their aunts, enacted the Cadonau Legacy Plan, which was supposed to prevent the company's liquidation by future generations of Alpenrose owners.

The siblings say they are suing for $35 million because that's the amount they say their aunts think the planned sale will net. They want a court order barring the aunts from unilaterally forcing through the liquidation plan.

Defendants Barbara Deeming and Anita Cadonau-Huseby could not be reached for comment. Phone messages left with Cary Cadonau, the siblings' lawyer, as well as Joseph Mabe and Carl Cadonau Jr. at the Alpenrose corporate office were not immediately returned.