Fires are not static things. They grow, split, merge, and perform in other ways that makes categorizing them into distinct entities a complicated task. During a large, multi-fire event such as the California Fire Siege of 2003 or the Northern California Firestorm of 2017, many factors can complicate the naming and counting of the number of fires involved. What a fire is called is a reflection of how first responders understand and manage fighting the fire, evacuating civilians, allocating resources, and more.
During the California Fire Siege of 2003, a fire originally known as the Verdale Fire started on October 24th, north of Highway 126. Fighting this fire was originally managed by a combination of LA and Ventura County departments. By October 25 the fire had been partially contained but had also crossed Highway 126 and was spreading south. The strategic decision was made to now treat this as two separate fires: the Verdale Fire north of Highway 126, which the firefighters were making good progress on containing, and the Simi Fire south of Highway 126, which was spreading extremely quickly and threatening over 6,000 structures. Road closures associated with the Verdale Fire were lifted, and management of the Simi Fire was assigned to a State Incident Command Team. Fires are not always split like this when they cross major roads. Nothing changes about the flames themselves when part of the fire is renamed, but renaming helps firefighters and emergency response personnel change their behavior and rethink how best to address the fire.
On October 8th, 2017, around 10 PM, a fire started on Norrbom Road in Sonoma, California. It would initially be called the Norrbom Fire. About twenty minutes later, another fire started on Nuns Canyon Road in Glen Ellen, California. Starting a couple of miles northwest of the Norrbom Fire, this fire was called the Nuns Fire. At some point it was decided that the Norrbom Fire, the Nuns Fire, and other fires that had started with distinct ignition points and names would all be called the Nuns Fire and treated as a single fire. Commonly, allusions to "the Nuns Fire" refer to the merged entity. However, in terms of fire command, it is important to differentiate between the Nuns Fire that started from one spot on Nuns Canyon Road, and the Nuns Fire that started out as multiple fires with multiple ignition points.
August 8, 2023: In Lahaina, on Maui Island, Hawaii, a brush fire started around 6:35 AM near Lahaina Intermediate School. Firefighters responded and used water tankers and bulldozers to put the fire out. They then returned to the fire station around 2:18. In the Lahaina Fire Comprehensive Timeline Report by the Fire Safety Research Institute, this initial fire is called the 'Lahaina AM' fire. At 2:55pm, the 'Lahaina PM' fire was reported in the same area. This is the fire that would rapidly grow to devastate the community and claim over 100 lives. The use of "Lahaina AM" and "Lahaina PM" as names for the two fires reflected an incomplete understanding of events. Later, the Lahaina Fire Summary of Findings and Conclusions report from the U.S. Department of Justice’s Bureau of Alcohol, Tobacco, Firearms and Explosive would report that the Lahaina AM and Lahaina PM fire were in fact one single fire: some smoldering material from the morning had reignited in a nearby gully.