PHOTO: Tuesday's high winds moved the Bighorn Fire along the Sutherland Ridge Trail where it meets the Mount Lemmon #5 Hiking Trail just east of Summerhaven, officials said.
That meeting point where the fire reached is about four miles from Ski Valley and about six miles from Summerhaven.
Fire crews responded to the fire's movement Tuesday with large airtankers to work the fire's edge and keep it from moving closer to the observatory, Rocky Gilbert, an operations section chief for the Southwest Incident Management Team, said in a video update Tuesday evening.
Mt. Lemmon including Summerhaven and Mt. Bigelow were evacuated Tuesday. Residents were asked to head south on Catalina Highway and leave the mountain immediately.
Pima County Sheriff Mark Napier said the sheriff's office is still evacuating residents in the area.