Stores in Colorado Springs, Fort Collins, Greeley and Longmont will hold strike-authorization votes tonight and tomorrow morning.

Safeway employees at a Denver store walked out Monday, expanding a strike that started this weekend. The strike started small with workers at three stores in Estes Park, Fountain and Pueblo, and a Denver distribution center.

Safeway and Albertsons workers in several Colorado locations went on strike, and many more stores are expected to strike soon.