Sawmill Fire (2017)

Wildfires are a natural part of the ecological cycle of the Southwestern United States.[1]^: 3–6 The Sawmill Fire was one of 2,321 wildfires that burned 429,564 acres (173,838 ha) in Arizona in 2017.[2] The State of Arizona expected a "normal" season but one with high fire potential in the state's southern grasslands because of high temperatures, low humidity, and an abundance of fuels.[3] By August 2017, wildfires had burned the most amount of land since the 2011 season.[4] In May 2018, the Ecological Restoration Institute at Northern Arizona University published a study of the 2017 wildfire season in Arizona and New Mexico and observed that more land had burned in Arizona than the average of the previous ten years. Eleven fires were studied, of which ten were in Arizona and included the Sawmill Fire.[5]^: 1

The fire began at around 11 am (MST) on April 23, 2017,[6] in the Coronado National Forest, a state-owned property in south-central Arizona,[7] 26 miles (42 km) south of Tucson, Arizona.[8] The cause of the fire was a detonation at a gender reveal party hosted by the Dickey family of a target packed with blue dye to indicate the male gender of their child, and Tannerite,[9][10] a highly explosive substance,[11] by Dennis Dickey, an off-duty U.S. Border Patrol agent and the child's father. Dickey fired at the target four times, striking and detonating it with the fourth shot;[12] the explosion immediately set the nearby grass on fire.[9][10] According to his attorney, Dickey attempted to put out the fire but was unsuccessful because of the speed at which it was spreading.[13][14] Afterward, Dickey alerted law enforcement and admitted culpability for the fire,[15][16] and subsequently cooperated with authorities.[15]

At the time the Sawmill Fire began, a fire warning for the area from the National Weather Service was in effect, as local wind speeds were as high as 40 miles per hour (64 km/h),[13] and precipitation was abnormally low for the region.[17] These conditions allowed the fire to spread quickly,[8][18] and by the time elements of the Green Valley Fire Department arrived at 11:11 am (MDT), the Sawmill Fire had grown to 300 acres (120 ha) and was spreading to the north and east.[18] Firefighters began to attempt suppression of the fire, which was difficult in the rough terrain of the Santa Rita Mountains. By April 24, the fire had consumed about 7,500 acres (3,000 ha), despite the assistance of five airtankers and three helicopters carrying water.[19] That night,[20] the fire crossed and damaged Arizona State Route 83,[21] which runs south through the Coronado National Forest and had been closed earlier that day,[22] and headed east across the Santa Rita Mountains.[14][20]

The burn scar of the Sawmill Fire seen from satellite on April 26

As the fire continued to spread, about 100 area residents were evacuated and 100 others east of Route 83 received pre-evacuation notices.[20][23][24] The local chapter of the American Red Cross opened two shelters in Sonoita and Tucson on April 24 and 25,[20][25] but they were almost totally unused[21] and were closed on April 29.[26] By April 25, 363 first responders were fighting the Sawmill Fire,[27] which had grown to 17,000–20,000 acres (6,900–8,100 ha)[28] because of continued low humidity and high winds that made aerial firefighting impossible.[20][23] Winds subsided the night of April 25–26,[29][30] allowing the now approximately 600 firefighters present to halt the southern spread of the fire near Empire Ranch,[21][31] where flames came as close as 50 feet (15 m) to the ranch's historic buildings.[32] The fire's area nonetheless doubled to 40,356 acres (16,331 ha) and conditions were expected to worsen because of a storm system in northern Arizona.[21][30] Arizona State Route 83 and Interstate 10 were closed on April 27.[31]

By 11:00 am (MST) April 27,[33] the Sawmill Fire had burned 46,954 acres (19,002 ha), and efforts to suppress it had by then cost $1 million (equivalent to $1.2 million in 2022[34]).[16] About 800 firefighters were present and made progress containing the fire with firebreaks on April 28 and 29,[22][33][35] despite aircraft again being grounded by the wind.[17] Route 83 was reopened and evacuation orders for people to its west were lifted on April 27.[33] Despite winds as fast as 45 miles per hour (72 km/h) on April 28,[16][22] the fire was fully contained and all evacuation orders were lifted by April 30.[36][37] The firefighters were demobilized on May 1.[38]

The Sawmill Fire burned 46,991 acres (19,017 ha) over 11 days,[5]^: 7 growing to its greatest extent on April 29,[6][39] and cost $8.2 million (equivalent to $9.8 million in 2022[34]) to suppress.[5]^: 7[6] The state-owned Santa Rita Experimental Range and Wildlife Area and the Las Cienegas National Conservation Area (LCNCA), managed by the Bureau of Land Management, made up most of the burned area;[14][40] 28% of the LCNCA, roughly 12,000 acres (4,900 ha), was burned and was closed from April 28 to May 23.[41][42] Of the total area burned, about a third of it suffered total foliage mortality, concentrated in the west. 412 people were evacuated,[5]^: 7 but there were no fatalities, serious injuries, or buildings destroyed.[13][14] After repairs to Route 83, it reopened in early May 2017.[36][43]