It took nearly 800 firefighters at a cost of $8.2 million to extinguish.
The flames turned into what became known as the Sawmill Fire, a blaze that torched approximately 182 square kilometres of land and caused an estimated US$8 million in damage near Green Valley, Arizona, in April 2017.
"Dickey started the fire by shooting a rifle at a target".
Footage of the incident was released by the US Forest Service on Monday.
An-off duty border patrol agent, 37-year-old Dennis Dickey, pleaded guilty to starting the "Sawmill Fire" last spring.
As part of their reveal celebrations, Dickey was to shoot at a target that was filled with powder, which would either burst and show blue (for a boy) or pink (for a girl) - sounds straightforward enough, doesn't it?
WATCH: Shocking new video shows Border Patrol agent’s planned explosion that started 47,000 acre wildfire
In the clip, as the grass catches fire, a man can be heart shouting: "Start packing up".
"I feel absolutely awful about it".
On April 23, 2017, the day the fire started, the Hopkins weather station not far from where the fire began near Madera Canyon, recorded a high temperature of 80 degrees, 11 miles per hour WSW winds gusting to 25, and 6 percent relative humidity.
He was ordered to pay a $100,000 (£78,000) fine up front and then $500 (£390) every month for the next 20 years.
He also agreed to conduct a public service announcement with the U.S. Forest Service about the cause of the fire. When he shot at, and hit, the target, he caused an explosion which ultimately set off a massive forest fire. After the ingredients are combined, the compound is illegal to transport and is classified as an explosive by the Bureau of Alcohol, Tobacco, Firearms.
'I don't believe' own administration's climate report
The National Academy of Sciences reviewed the report, and one of the members said this: "We have wasted 15 years of response time".