California's Shasta County is dealing with the 6th-worst fire in state history, which has killed 6 people and burned over 130,000 acres. The Carr fire, which is just 39% contained and being fought by oiver 4,300 fire personnel, has destroyed over 1,500 structures and is threatening another 1,300. Thousands of residents have been evacuated, while Yosemite Valley gave people until Noon on Friday to leave the area.
Large fires such as the Carr can produce their own unique weather paterns - and this was no exception. On July 26, the inferno unleashed a "fire tornado" that was so strong it uprooted trees and stripped away their bark. The National Weather Service on Thursday said that the vortex reached in excess of 143 MPH - equivalent to an EF-3 on the enhanced Fujita tornado scale.
The NWS & @CAL_FIRE Serious Accident Review Team (SART) are conducting a storm damage survey regarding the large fire whirl that occurred Thursday evening in Redding. Preliminary indicators placed max wind speeds achieved by the fire whirl in excess of 143 mph. #cawx #CarrFire pic.twitter.com/3iRX90lhLJ— NWS Sacramento (@NWSSacramento) August 2, 2018
“This is historic in the U.S.,” Craig Clements, director of San Jose State University’s Fire Weather Research Laboratory, told BuzzFeed News. “This might be the strongest fire-induced tornado-like circulation ever recorded.”
Known as a pyrocumulus cloud, the ominous red weather formations usually occur over volcanic eruptions or forest fires when intensely heated air triggers an upward motion that pushes smoke and water vapor to rapidly rise. They can develop their own weather patters, including thunderstorms with severe winds which then further fan the flames.
The tornado formed as the blaze, which has already charred an area three times as large as the District of Columbia, erupted and began to rotate like a supercell thunderstorm. Initially the smoke plume reached about 20,000 feet. That’s not overly impressive for a thunderstorm, but it couldn’t rise any higher: It was trapped beneath an inversion.
That “cap” in the atmosphere caused the smoke to spread out. But around 7:15 p.m. Pacific time, two plumes suddenly managed to break the cap. They rose into an unstable environment and exploded upward, towering to nearly 40,000 feet within just 30 minutes. That extreme, rapid vertical growth of the fire fueled an updraft that eventually would spawn the tornado. -WaPo
How crazy is this?— Kimberly Kolliner (@KimberlyKTVL) July 28, 2018
A pyrocumulus cloud formed from the #CarrFire...
If it gets big enough it can create a microclimate, which means more winds and the possibility for lightening.@Milt_Radford @RandiBurnsKTVL @AutumnKTVL
Can you help us understand how these form? pic.twitter.com/PBQx6PDdkw
Fire map of California: