The group became separated while fighting the nearly 2,000-acre Yarnell fire located 85 miles northwest of Phoenix.
Officials instructed residents to evacuate about 50 homes. The fast-moving blaze has been burning since Friday, destroying at least three homes and causing injuries in the area.
The fire was zero-percent contained as of Sunday evening.
About 250 firefighters are currently on the scene, with 400 more expected to arrive soon.
This post will be updated as we learn more.