Mount Lemmon and the community of Summerhaven were evacuated Tuesday as crews worked to battle the growing Bighorn Fire.

Residents were asked to head south on Catalina Highway and leave the mountain immediately. The Pima County Sheriff’s Department sent personnel to go door to door to tell residents to leave.

The notice to clear out came on the eve of the 17th anniversary of the start of the Aspen Fire that devastated Summerhaven in 2003.

Also, an area lower on the mountain was placed in the “set” status to prepare for a possible evacuation.

A Chinook helicopter drops water on a ridge above Pima Canyon in Coronado National Forest during the Bighorn Fire on June 10, 2020. Video by Rick Wiley / Arizona Daily Star

That area covers Organization Ridge Road — site of several camp locations — to Willow Canyon.

Officials have closed much of the Coronado National Forest in the Catalinas as well as Catalina State Park and the highway up to Summerhaven because of the stubborn fire.

As of Tuesday, the lightning-sparked Bighorn Fire had grown to 15,805 acres, but progress has been made, with containment reaching 40%.

The evacuation zone has about 150 residences, though it’s uncertain how many of the homes were occupied, said Deputy Marissa Hernandez, spokeswoman for the Sheriff’s Department.

The general boundaries of the evacuation zone are Mount Lemmon and Mount Bigelow north of Organization Ridge Road, including Summerhaven. The evacuation notice was issued just before 1:30 p.m. Tuesday.

UA officials said observatory sites at the summit of Mount Lemmon and on Mount Bigelow were evacuated.

“Both observatory sites in the Catalinas ... fall within the mandatory evacuation ‘Go’ zone. Therefore we have suspended all telescope operations,” said Eric Christensen, senior staff scientist at the University of Arizona’s Lunar and Planetary Laboratory and director of the Catalina Sky Survey.

Catalina Sky Survey is a NASA-funded project based at the UA with a mission of discovering and tracking near-Earth objects. Researchers utilize three telescopes owned by the UA’s Steward Observatory.

Jenni Zimmerman, who grew up on Mount Lemmon, said she is scared to see the mountain burn. The village was devastated by the Aspen Fire two days after it started on June 17, 2003.

Zimmerman’s parents own Mount Lemmon Realty, and the Zimmerman family has been selling property on the mountain since 1941.

She is a broker for her parents’ business and serves as the vice president of the Mount Lemmon Home Owners Association and the president of the Mount Lemmon Business Economic Association.

The Zimmerman family has lived and worked on Mount Lemmon for four generations, since Jenni’s grandfather took his family up the mountain in 1937.

“My whole family has been up there for all these years,” she said.

“We have so much invested, not just financially but emotionally, so it’s very stressful.”

The last time Mount Lemmon was evacuated was July 2017, when the Burro Fire burned more than 21,000 acres in the Santa Catalina Mountains and near Redington Pass, getting close to Summerhaven.

Zimmerman said it’s stressful to see the fire, especially when she got a phone call telling her to tell everyone she knows on Mount Lemmon to get off the mountain.

“I have all the faith that the Forest Service is doing what they can but they’re not God,” Zimmerman said. “They can’t fix the wind.”

She said she hopes people will support the businesses on Mount Lemmon once the fire subsides and they are able to reopen.

As someone who visits Mount Lemmon weekly to hike, Kira Geddes said it’s heartbreaking to see the fire get closer to Summerhaven.

Geddes owns Casa Kira, a jewelry business, and sells her jewelry to Living Rainbow Gift Shop on Mount Lemmon. She said being able to go up Mount Lemmon is part of life as a lifelong Tucsonan.

“These thousands of acres mean a lot, they mean a whole lot to a lot of us as Tucsonans,” she said.

An evacuation center was opened at Sahuaro High School, 545 N. Camino Seco. Large animal sheltering will be done at Rillito Racetrack, 4502 N. First Ave.

The Pima Animal Care Center will also house pets. The after-hours number is 724-5900, Extension 4.

For more information, Mount Lemmon residents can call 351-3473.

Storms to the south and east of the blaze on Monday limited the fire’s spread, but windy conditions and low humidity are expected on the mountain Wednesday.

On Tuesday, firefighters focused on creating defensible space around Summerhaven, using bulldozers and excavators to bolster fuel breaks, in the event that the fire moves up the mountain.

Crews started placing bright orange portable water tanks known as “pumpkins” among the homes in the community to feed sprinkler systems and firehoses on Tuesday.

Officials are also looking at where the fire could impact Sabino Canyon, which is closed to the public, as the blaze has backed its way up into the west fork of the area.

On Monday night, crews took advantage of favorable weather to conduct burnout operations on the northeast portion of the fire near the Trico powerline corridor.

The goal of the burnout, conducted through aerial ignition using helicopters, is to slow the upslope momentum of the fire as it emerges from Romero Pass, officials said.

There are 729 people working the blaze, including seven hotshot crews.

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Reporter Shaq Davis contributed to this story.