Smoke from the Bighorn Fire as seen from Summerhaven on Sunday afternoon. The wildfire grew to more than 12,000 acres as of Sunday morning and was 11% contained, fire officials said.

 Rebecca Sasnett / Arizona Daily Star

Residents in Mt. Lemmon including Summerhaven have been asked to prepare for evacuation in case the Bighorn Fire conditions change.Β 

The area of Mt. Lemmon and Mt. Bigelow just north of Rose Canyon Lake is now in "set" orders, where residents are urged to voluntarily leave or be prepared to evacuate.Β Β 

Catalina Highway is closed at milepost zero and only residents and business owners are allowed in, the Pima County Sheriff's Office said.Β 

The East Golder Ranch Drive and East Rollins Road area where residents were asked to evacuate Saturday was back to "set" orders Sunday as well.Β 

Residents in those areas can call 520-351-3473 if they have questions about the fire.Β 

Fire crews moved into the Summerhaven community as they worked to protect Mt. Lemmon from the raging Bighorn Fire Sunday.

The fire activity on the western edge of the massive lightning-sparked wildfire has the potential to move into the Mt. Lemmon area, Rocky Gilbert, an operations section chief for the Southwest Incident Management Team, said in a video update Sunday afternoon.

The fire grew to 12,345 acres by Sunday morning, up from 11,500 Saturday night, and was just 11 percent contained after burning for more than a week.

Fire supervisors spent Sunday near Summerhaven improving fire breaks, or gaps in fuels and vegetation, in case the fire moves closer to that area, Gilbert said. Crews plan to open a camp at Rose Canyon Lake in the next two days.

β€œWe’re trying to plan ahead for (the) worst-case scenario,” he said.

Gilbert said there is also still a lot of unburned fuel between where the fire is active on the southwest end and the communities in the Ventana Canyon area. Crews aim to have plans in place in case the fire starts to move south again.

Fire crews made significant headway protecting the Golder Ranch, Oracle and Catalina State Park areas overnight Saturday so they could look toward Ventana and Mt. Lemmon, Travis Mabery of the Southwest Incident Management Team said at a media briefing early Sunday morning.

Sierra National Forest hotshot crew members talk about wind patterns while preparing for a possible change in direction from the Bighorn Fire on Mount Lemmon in the Santa Catalina Mountains in Ariz. on June 14, 2020.

β€œWe are doing our due diligence, making sure we’re ready if it ever does move up there,” he said.

On the west and south ends of the fire, containment lines haven’t moved for several days, Gilbert said.

The fire on Sunday was most active in the Pusch Ridge Wilderness around Romero Canyon and Cathedral Rock, with dark smoke visible from the Tucson metropolitan area.

Crews will continue to drop fire retardant over the heart of the fire, but there’s not much more crews can do there because the terrain is so rocky, Mabery said.

β€œWe can’t safely put people into the wilderness,” he said. β€œThere’s no way to pull them out if things go bad.”

While Mabery said the 560 people fighting the fire are making good progress, especially along the fire’s western and southern edges where many Tucsonans live, he emphasized there is still a high potential for threat if winds shift or conditions otherwise change.

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