According to Fox news
An explosive wildfire burning in Northern California whipped up a rare and dangerous fire tornado on Saturday, triggering a dire warning from forecasters.
The Loyalton Fire has burned some 20,000 acres north of Lake Tahoe since igniting Friday afternoon and is only 5% contained, according to Tahoe National Forest.
Mandatory evacuations are in place for portions of Plumas, Lassen, and Sierra Counties as the blaze is burning east of the town of Loyalton and southwest of Mount Ina Coolbrith.
On Saturday afternoon, the National Weather Service (NWS) office in Reno warned that the blaze had “extremely dangerous fire behavior,” with the potential for rotating columns and fire whirls, otherwise known as fire tornadoes or a “firenado.”
About 20 minutes after, forecasters warned responders to beware of a rare fire tornado near Roberts Canyon.
“Heed all orders by emergency managers and responding personnel,” the forecast office tweeted. “Stay away from the fire area!”
Pyrocumulus FIRENADO timelapse
Date: Aug 15,2020
Time: 2:06 PM
Location: CA State Hwy intersection 395 and 70#loyaltonfire#firenado pic.twitter.com/8YuIssdKg9— Barry Winston (@BSWinston) August 16, 2020
Fire tornados, also known as 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.
Weather service officials said Saturday that the Loyalton Fire was showing extreme behavior, such as gusty winds and blowing smoke, similar to a deadly Northern California fire that destroyed more than 1,000 homes and killed 8 people
“Firenadoes are an extreme weather phenomenon that can occur with rotating fire columns,” the NWS Reno tweeted. “As extreme as this behavior is, the #CarrFire had an extreme example of this.”
It may have been the first time the NWS has issued a tornado warning, according to the San Francisco Chronicle.
“We really don’t have any other product for that type of situation,” NWS meteorologist Wendell Hohmann told the paper. “We decided to put a tornado warning out on it and emphasize the significance.”