Chico, California— As a raging wildfire destroyed homes and burned more than 160,000 acres near Chico, California, cameras along the fire line captured another horrific sight: flames.
There was no severe weather in sight, but the intense heat from the park fire created its own weather system — a swirling, swirling menace that was a surreal mix of wind, smoke and flames.
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“The vortices these fires create form in an environment where there's rotation and shear,” said Fox Weather meteorologist Bob Van Dillen. “Now, with regular tornadoes, the rising air Often caused by differential heating of a major weather system…” Cold air aloft causes warm air near the surface to rise, creating convection and storms.
But in the case of a fire tornado, its development is triggered by high temperatures at the surface and large amounts of rising air.
“Think about a difference in heating time of about 100 times,” Van Dillen said. “A lot of heat is being generated here.”
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As air rushes in to replace the rising air, if there is enough wind shear, the column will begin to rotate.
The National Weather Service Doppler radar near Oroville captured the rotating winds Thursday night, giving a radar signature that looked more like the signature of Tornado Alley.
“The winds were flowing in one direction; the winds were flowing in the opposite direction, right next to each other,” Van Dillen said. “To me, it looked like a real supercell tornado forming… so it was a rolling fire tornado. (Steven) Spielberg couldn't think of anything like this.”
In addition to the dangers of being near a flame-filled vortex, fire tornadoes can throw embers away from their current footprint, starting new fires beyond containment lines.
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The most feared fire tornado occurred during the massive Carr Fire that struck Northern California in July 2018. Stretching to 40,000 feet high, it sparked supercell-like fires.
A tornado of similar intensity would correspond to an EF-3 rating on the Enhanced Fujita Scale.
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There have been no reports of any injuries or other damage from the Park Fire tornado. But officials say the Park Fire has destroyed “many” homes so far. More than 4,400 people have been evacuated and more than 1,100 firefighters are on scene battling the blaze.
Investigators said the cause of the fire was arson and the suspect has been detained.