Calif. fire tornadoes had winds up to125mph
California’s Creek Fire, which has torched nearly 300,000 acres and become the state’s largest wildfire on record, was still only a third contained as of Wednesday. Like other blazes this year, it grew rapidly in size during periods of hot and dry weather with strong winds, burning tens of thousands of acres in a single night.
Now we know that the fire featured a rare phenomenon that demonstrates just how extreme it was, with the National Weather Service’s announcement Wednesday afternoon that two fire tornadoes were associated with this blaze.
The two vortices, one rated an EF2 and the other an EF1, were produced by the fire, as the extreme heat from the blaze and towering smoke plume above it essentially created its own weather.
Unlike firewhirls, which can commonly be seen forming from the ground up over campfires and even small brushfires, fire tornadoes
are actual tornadoes. They are born from rotating clouds orsmoke plumes in environments where winds change speed and/or direction with height. The funnels themselves aren’t filled with fire, but rather a superheated column of smoke, ash and debris.
Two tornadoes have been confirmed thus far fromthe blaze Sept. 5 — one near Mammoth Pool Reservoir in the Sierra National Forest well southeast of Yosemite and one near Bass Lake, about 5 miles east of
Oakhurst.
The National Weather Service in Hanford, Calif., which was responsible for rating the tornadoes, determined their strength based on observed tree damage.
Jerald Meadows, warning coordination meteorologist at the Hanford office, said both tornadoes shared some common features.
“The main contributing factor was the debarking of all the pine trees up with the Mammoth Pool tornado,” Meadows said. “They both uprooted trees to the root balls and snapped large pines. But the (Ef1tornado) did not have any signs of true debarking. We’re probably talking the difference between100 and 110 miles per hour.”
The Mammoth Pool tornado, which touched down inside the Wagner Campground, snapped several 2foot-diameter trees about 20 to 30 feet above the ground; it was rated as having winds of 115 to 125 mph. The Bass Lake fire tornado had winds of 90 to107 mph, and the NWS noted that it was “the result of unprecedented fire activity.”
The EF2 tornado near Mammoth Pool was associated with an impressive radar signature at 3:17 p.m. local time Sept. 5. The smoke plume associated with the Creek Fire had towered to 41,000 feet — the height of a strong thunderstorm — and the entire plume was rotating clockwise at the time. That’s opposite to how most tornadic thunderstorms in the Northern Hemisphere spin.
Shortly after the tornado occurred, the plume billowed to what one fire researcher referred to as an “insane” 55,000 feet. That means that the plume was probably in the process of undergoing quick vertical development with a strengthening updraft at the time of the tornado, which likely aided in its formation.
“A tornado warning was considered but not issued,” said Meadows, who feared that disseminating such an alert might leave people unnecessarily conflicted about deciding whether to shelter or evacuate.
“A tornado warning for a fire opens up a can of worms,” he said. “We want to make sure we’remessaging properly, and we were talking to fire crews letting them know of the circulations we were seeing.”