Catastrophic fire tornadoes are a terrifying new phenomenon
The titanic fire tornado that killed a firefighter and ravaged Redding on July 26 as the Carr Fire hit its peak has presented fire crew leaders with a frightening new challenge: how to battle a raging cyclone of flame.
There are no immediate good answers, experts say, because the kind of tornado that overcame Redding fire inspector Jeremiah “Jeremy” Stoke in a matter of seconds is too big, fast and powerful to stop. It’s also nearly impossible to predict.
What’s worse, according to
fire behavior experts, is that the kind of extreme fire behavior that killed Stoke is becoming more frequent, more violent and more destructive.
“We are setting new modern records, and it seems like the old rules are out,” said Dave Sapsis, the senior fire scientist for the California Department of Forestry and Fire Protection, known as Cal Fire. “We’re just having more frequent and more extreme conditions under which these fires are burning.”
Smaller “fire whirls” have always been a hazard, but fire experts say dramatic events like the massive Carr Fire tornado have, until now, been extremely rare.
“Fire whirls occur all the time. What was unusual about this one was the strength of the surface winds and the size,” said Craig Clements, director of the Fire Weather Research Laboratory at San Jose State University. “This was a meteorologic phenomenon.”
Fire tornadoes represent the convergence of multiple threats: intensely hot weather; a profusion of dry fuel, wind and terrain that accelerates the spread of flames and creates whirls of spinning air. Sapsis said in this instance, the Carr Fire tornado was created when hot air crested over a ridge and was met by stable air down in the valley, causing it shoot up in a vortex.
What makes tornadoes so dangerous is their chaotic nature, experts said. Once a tornado of any size forms, “they move independent from the fire,” said Bret Butler, a research mechanical engineer with the U.S. Forest Service who studies fire behavior and conditions.
“They’re amazing to watch, but they’re unpredictable and you need to get a safe distance away, which is much farther than we have been in the past,” he said. “If it was me, a mile or 2 miles away.”
In its Green Sheet follow-up report, Cal Fire said when a fire tornado is spotted, “move as far away as possible to a safe location.”
The report detailed, minute by minute, how quickly and unexpectedly the tornado appeared on the July evening, when temperatures spiked to a record 113 degrees as the Carr Fire raged out of control in and around Redding.
And while it doesn’t assign blame in the deaths of Stoke and Don Ray Smith, a bulldozer operator who was killed earlier that day in a burn-over, the report does lay out lessons learned from the tragedy.
The Redding tornado was the worst of any kind ever seen in California, with a base the size of three football fields, winds up to 165 miles an hour and temperatures of at least 2,700 degrees — nearly double the temperature of a typical wildfire. Fire tornadoes also raged through Santa Rosa last year during the Tubbs Fire and other Wine Country fires, but they weren’t as gigantic or powerful as the massive flaming vortex in Redding.
Scott Stephens, a professor of fire science at UC Berkeley, said most fire whirls are small, maybe 6 to 8 feet tall, and disappear in a few seconds. “This was a totally different beast,” he said.
Different, yes — but as it turns out, not entirely unheard of in history.
In 1926, a fire whirl in San Luis Obispo lifted an entire home into the air and carried it across a field, killing two people. An enormous fire tornado, called a “dragon twist,” erupted in Japan after a deadly earthquake and tsunami in 1923, immolating 44,000 people who had sought refuge in wooden structures near Tokyo’s Sumida River.
The difference now, Sapsis said, is that “we are now seeing them popping up outside the normal places and conditions that we are used to seeing.”
While smaller fire whirls aren’t necessarily more dangerous than the fire alone, larger tornadoes can cause as much damage from their extreme winds as from the flames they cast about.
Scott McLean, a Cal Fire spokesman, drove through Redding neighborhoods that had been at the center of the Carr Fire tornado the morning after it tore through. “You had homes that were still standing and untouched by fire, but they were heavily damaged by the wind and debris that was flying around. Huge trees were uprooted and lying across the roads,” he said. “And you go down a couple blocks and homes are destroyed by fire.”
As it ripped across the rural town of 91,000, the tornado’s ferocity was so intense that three bulldozers and two Cal Fire trucks on its periphery were nearly destroyed by its wind.
“All three dozers were violently impacted by flying debris, rock, embers, smoke and intense heat,” the report said. One dozer crashed against a tree, and all the operators wound up fleeing for their lives. Similar destruction happened to the truck drivers.
As scientists begin to assess the specifics of the tornado, Cal Fire’s conclusions in the Green Sheet offer some starting points. McLean said that up and down the state, Cal Fire staff are studying the report for clues to predicting future events and developing safer strategies for handling a tornado of any size.
“Be aware that winds along a fire tornado’s base can be very high due to the vertical movement of air and gases in the core of the rotating plume, creating a very strong indraft at the tornado’s base,” the report said. “This indraft can be a significant threat to human safety, especially to pilots flying aircraft in the area.”
It advises that any firefighting crews in the vicinity “maintain constant communications with supervisors and adjoining forces.” And, it said, they should keep in mind that “once a fire tornado appears to dissipate, it may redevelop and result in additional injuries and damage.”
One worrying factor is that fire analysts can read conditions and determine that a large tornado is possible, but they cannot predict that one is imminent, experts said.
Clements at San Jose State said his lab has equipment that can be transported to the scene of a fire to assess tornado possibilities, but it’s expensive and can’t often be mobilized quickly enough for the rapidly changing conditions of a wildfire.
With small fire whirls, firefighters often can just wait for them to dissipate in a matter of seconds, McLean said. Even with a larger tornado in a desolate area, crews can likely afford to stand down while the winds whip up flames — if they see it in time.
However, what made the Redding tornado especially devastating, aside from its sheer size and power, was its location — firefighters and other emergency responders had a duty to see people safely out of the area as best they could, McLean said. They couldn’t afford to wait it out.