The accident occurred around 1:30 p.m. in an orchard near Schrader Road.
The Yakima County Sheriff's Office says the woman was working from a motorized platform above the ground when it fell over.
The woman suffered injuries to her arm and shoulder. Two other workers on the platform were not hurt.
Authorities say it appears the platform tipped because it was on sloped, uneven ground. The accident will be forwarded to the state Department of Labor and Industries for review.