Lightning is blamed for causing one of the two devastating wildfires that tore through parts of southeastern New Mexico last month.
Federal, state and tribal officials said they identified where the South Fork Fire started, and "human activity and factors did not contribute to the cause."
The South Fork Fire and the Salt Fire broke out on June 17 in the same general area, near the village of Ruidoso. Thousands were forced to flee their homes as the fire closed in on the village.
Two people died and more than 1,400 structures were damaged in the fires, which are both now about 90% contained.
President Joe Biden approved a major disaster declaration for New Mexico, freeing up federal funds that will assist affected individuals, households and businesses in the area.
“This federal assistance will help affected residents receive the necessary aid to begin to recover and rebuild their lives,” New Mexico Gov. Michelle Lujan Grisham said.
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Firefighting efforts have considerably drawn down since the fires' peak. There are now only three crews, six engines and one helicopter tending to the fires.
"Fire activity remains limited on the South Fork and Salt fires," fire officials said on Thursday. "Hot spots remain within dense large, dead/down fuel, dense conifer stands and snags. These heat sources do not threaten containment lines."
While the cause of the South Fork Fire has been determined, officials are still investigating how the Salt Fire started.
If it's determined the fire was caused by a person, the FBI is offering a $10,000 reward for information leading to the arrest and conviction of that individual.
