Fire tornadoes are real — here's the science
Some are true tornadoes born from a wildfire's own thunderstorm. Others are "fire whirls" that look like tornadoes but are technically not. The distinction matters more than you'd expect.
The term "fire tornado" gets thrown at everything from a burning dust devil to a mile-wide firenado throwing burning trees a hundred yards. Meteorologists distinguish three overlapping phenomena. Only one of them is technically a tornado in the same sense as an EF-scale tornado.
1. Fire whirl
The most common. A rotating vortex of flame and hot air pulled from the ground into the atmosphere, driven entirely by the fire's own heat and any local terrain-driven wind. Fire whirls are typically 3-30 feet wide, last seconds to a couple of minutes, and are essentially fiery dust devils.
Fire whirls happen at almost every large wildfire. They're dangerous to firefighters but usually short-lived and small.
2. Firenado (large fire whirl)
Bigger, longer-lived versions — 100+ feet wide, minutes long, capable of moving mobile vehicles and throwing flame long distances. The 2020 Loyalton Fire in California produced a large firenado documented on video, and the NWS Reno issued the first-ever US "Fire Tornado Warning" during it. Still not a "true" tornado — it doesn't have a mesocyclone parent.
3. Pyrotornado (true fire tornado)
The rare and terrifying one. When a wildfire generates enough heat to launch a plume high into the atmosphere, it can form its own thunderstorm — a pyrocumulonimbus or "pyroCb." Occasionally that pyroCb behaves like a supercell, developing a rotating updraft (mesocyclone), and can drop a real tornado to the ground. This has happened at the 2003 Canberra bushfires (Australia) and the 2018 Carr Fire in California.
The Canberra fire tornado of January 18, 2003 was rated F3 (about EF3 equivalent, 160+ mph winds), destroyed 500 homes, and is the first officially documented true fire tornado in modern history. The Carr Fire tornado was rated EF3 with winds up to 143 mph and killed 4 people.
What makes a pyrotornado a real tornado? It's generated by a genuine thunderstorm — a pyroCb with a rotating updraft — rather than by fire heat and outflow alone. It also persists after the fire's direct plume weakens, meaning it's driven by atmospheric dynamics, not just flame.
How pyrocumulonimbus form
Wildfires release enormous amounts of energy — a large fire radiates as much heat per hour as a nuclear power plant. That heat drives a strong updraft. Smoke, water vapor from burning vegetation, and entrained air all rise together.
If the atmosphere above the fire is unstable — the same instability meteorologists measure as CAPE for regular thunderstorms — the fire's plume can grow into a full-sized thunderstorm complete with an anvil, lightning, and downdrafts. Add ambient wind shear and the pyroCb can begin to rotate.
The 2018 Carr Fire pyrocumulonimbus reached over 40,000 feet. NEXRAD radar in California detected it as a thunderstorm. The rotating updraft dropped a documented tornado, and the resulting damage path was surveyed and rated exactly like a regular tornado.
Documented fire tornadoes
- Canberra bushfires (Australia, 2003) — F3-equivalent, first officially documented true fire tornado.
- Carr Fire (Redding, CA, 2018) — EF3 with 143 mph winds, 4 dead.
- Loyalton Fire (CA, 2020) — large firenado, first US Fire Tornado Warning issued.
- Camp Fire (Paradise, CA, 2018) — multiple fire whirls but no tornado ranking.
- Great Kanto earthquake fires (Japan, 1923) — a massive fire whirl killed ~38,000 people at the Rikugun Honjo Hifukusho military clothing depot.
Why they're getting more common
Larger, hotter wildfires produce more energy and are more likely to drive pyrocumulonimbus formation. Longer fire seasons, drier fuels, and hotter atmospheres all favor pyroCb development. Australia's 2019-2020 Black Summer produced approximately 40 pyroCbs — an unprecedented count. California's fire seasons since 2015 have routinely produced them.
What to do near a pyroCb
- Evacuate. Wildfire evacuation orders during pyroCb activity are life-critical.
- Don't drive through smoke plumes with visible rotation. Vortex activity can flip vehicles.
- If sheltering in place is unavoidable, follow both wildfire safe-shelter rules (interior room, water) and tornado safe-shelter rules (interior lowest floor, cover head).
- Monitor NWS as well as local fire agency alerts. NEXRAD sees pyroCbs and NWS offices issue warnings.