The Burro Fire east of Tucson has grown to more than 25,000 acres, but crews have made some progress in containing the blaze. Incident Commander Bea Day said in a press release that containment of the fire was at 11 percent, as of Thursday afternoon.

Catalina Highway, Redington Pass Road and the Mount Lemmon Service Road remained closed Thursday, allowing officials and fire personnel to move unencumbered in their efforts to fight the fire. Residents of Summerhaven were still barred from returning home.

The origin of the fire, first reported on June 30 in the Burro Tank area of Redington Pass, is still under investigation. Nearly 700 fire personnel from 16 crews are on assignment, with eight helicopters and 47 fire engines to help combat the fire.

Considerable progress was made along the fire’s southeastern front on Wednesday, said Bea.

“Fire crews will continue to strengthen fire lines and do mop up work to ensure that the fire does not escape containment,” he said.

However, the northeastern boundary of the fire continues to burn unabated. The area is too dangerous to send personnel in by foot, with the steep terrain offering few escape routes for firefighters and ample fuel source for the fire.

Instead, crews are using helicopters and water tankers to drop slurry on the blaze while at the same time “making contingency plans so they will be prepared if the fire should attempt to spread into the rugged country beyond the existing perimeter,” Day said.

Crews were also working to protect structures along Catalina Highway. Brush and debris were removed from the area, with contingencies made for defending homes'

“Firefighters are positioned for a possible defensive burning operation between the highway and the fire’s edge should the fire make an aggressive run to the west,” Day said.

Less-than-ideal weather has also slowed efforts. Crews will be battling more than just the fire this  weekend, with an extreme heat advisory in effect for the area through Friday. Forecasts do call for some monsoon activity on Saturday or Sunday, however.

During Thursday mornings incident briefing, Day took a moment to remember the importance of the date. “On this day 23 years ago, 14 firefighters lost their lives on the South Canyon Fire” in Colorado, he said.

Then he warned the firefighters to be careful out there.

“There is nothing on that mountain worth dying for,” Day said. “Keep your head on a swivel, watch out for each other and come back here safe tonight at end of shift.”