(CNN)A fire in the Tucson area has grown to thousands of acres and is threatening hundreds of homes.
The Bighorn fire was sparked by lightning in Pima County on June 5.
By late Thursday, the fire had grown to 6,200 acres and was 10% contained, according to the Coronado National Forest. Authorities have issued mandatory evacuation orders for about 200 homes.
The fire "threatened approximately 850 homes around Oro Valley and the Catalina Foothills," according to a news release from the Federal Emergency Management Agency.
FEMA on Thursday authorized the state of Arizona's request for federal funds to combat the blaze, saying in its release that the threatened destruction would constitute a major disaster.
At least 419 fire personnel are battling the fire which is located in the Santa Catalina Mountains.
Over Thursday, crews conducted burnout operations, which involves dropping small plastic spheres that ignite when they hit the ground to burn the vegetation in the path of the fire so it eventually runs out of fuel, according to CNN affiliate KOLD.
But the fire continued to burn through the night.
Weather is a concern for much of the region on Friday.
More than 6 million people across Nevada, Arizona, Utah and eastern California are under red flag warnings through Friday evening.
Strong winds are possible for the area that is already prone to dry, hot conditions which could produce rapidly spreading fires through the weekend, according to CNN meteorologist Haley Brink.
Across the Southern Rockies and Southern High Plains there is a chance for dry thunderstorms where lightning could threaten to start new fires, Brink said.