Fire managers on the Coconino National Forest will be back to work Thursday on a prescribed burn 15 miles southeast of Flagstaff just north of Mormon Lake. Officials say 919 acres will burn to protect the Pine Grove campground and Lake Mary Road corridor. Smoke will be thicker and more noticeable due to the amount of fuels in the area. Smoke is expected to move to the southwest, which may impact Lake Mary Road, Interstate 17, Mormon Lake Village and Munds Park. The burn is expected to be a one-day event.