The U.S. Forest Service said Monday the blaze spawned fire whirls, which caused “rapid growth” of the blaze.
“These occur when intense rising heat and turbulent wind conditions combine to form whirling eddies of air and are an indication of extreme fire behavior,” officials said on Facebook.
Fire tornados, also known as fire whirls or fire vortices, are not tornadoes in the true sense. They occur when a gust of extremely hot air blows through the fire at a certain angle, producing a spinning momentum which then sucks up embers and debris.
Last month, another explosive fire in the northern part of California whipped up a fire tornado that caused weather forecasters to actually issue a tornado warning due to the conditions.
In 2018, the massive Carr Fire in California produced a vortex with winds clocked at 143 mph by the National Weather Service (NWS), a wind speed equivalent to an EF-3 tornado on the Fujita scale.
The Mono County Sheriff’s Office said the Slink Fire made a “significant run” toward the towns of Coleville and Walker on Monday before easing overnight.
Evacuation orders for Walker and Coleville were lifted Tuesday as air quality improved allowing for aircraft to continue assisting ground crews, according to the US Forest Service.
U.S. Highway 395 is also now open to traffic.
Due to the proximity to the Marine Corps Mountain Warfare Training Center, officials said the Marine Corps personnel have offered assistance. The forest service said they are being utilized in several ways to support the fire camp and logistical needs.
“The cooperation between the Marine Corps and the Incident Management Team has been outstanding,” Scott Fraser, Sierra Front Team 2 incident commander, said in a statement. “They have been a valuable asset and we greatly appreciate their help. When we have needed anything, we didn’t even have to ask, they were already doing it.”
Officials said extreme fire behavior is still observed on portions of the blaze, which is burning through mixed conifer, pinyon-juniper, sage and grass.
It’s estimated the blaze won’t be contained until Sept. 20.
Officials are concerned about a significant heat wave projected to start Thursday and last through Labor Day weekend. A dry, unstable airmass could lead to an increase in fire behavior in time for the holiday weekend.