Despite the efforts of more than 1,400 firefighters, the Pioneer Fire near Lowman has grown from 16 square miles late last week to 65 square miles Tuesday, and estimated date of containment has been extended to mid-September.
The fire was ignited July 18 by an as-yet unknown cause about eight miles northeast of Idaho City.
Depending on prevailing winds, smoke from the fire has been drifting in an out of the Wood River and Sawtooth valleys and has been dense at times. The Idaho Department of Environmental Quality has issued an air-quality caution for Blaine County through today, Aug. 3, advising people who are unusually sensitive to air pollution to refrain from physical exertion.
Fire crews had been clearing vegetation from along state Highway 21 south of Lowman in an attempt to use it as a fire break. According to a map posted on the Inciweb website, the fire breached that line over the weekend and has now burned about as much area on the east side of the highway as it had on the west. The fire is burning across about a six-mile-wide front from about four miles south of Lowman to about More’s Creek Summit.
The U.S. Forest Service reported that wind, heat and low humidity have combined into perfect conditions for burning over the past few days, allowing the fire to make significant gains to the east.
“The fire continues to exhibit extreme behavior with crown runs and mid-range spotting,” the Forest Service reported on the Inciweb site Tuesday.
Resources in use fighting the fire include 51 engines, 10 helicopters, eight dozers and 13 water tenders. The suppression effort thus far has cost more than $13 million.
Thirty-five people have been evacuated and two backcountry yurts have been destroyed. Ten other buildings are threatened.
Fire containment estimates have been reduced from 35 percent last week to 28 percent Tuesday. The estimated date for full containment has been extended to Sept. 15, from Aug. 12 on Monday.
On Sunday for the second consecutive day, a drone sighting grounded aircraft for about 45 minutes. The grounding took place at a critical time in the afternoon when aircraft are needed the most, fire spokesman Jerry Rohnert said.
Highway 21 is closed from six miles north of Idaho City to two miles south of Lowman.
Hot and windy conditions are expected to prevail again today, and the Forest Service predicts that the fire will continue to spread north and east.
The Comet Fire, which was started by lightning on Tuesday, July 26, about 13 miles north of Salmon, is now 83 percent contained and has not increased in size over the past few days. By Tuesday, it had burned 357 acres on the west side of the Salmon River and U.S. Highway 93.