NASA is using aircraft and satellite observations to study a dangerous and still poorly understood wildfire phenomenon: towering clouds of smoke known as pyrocumulonimbus, or pyroCbs. In an official NASA Earth Observatory report, researchers describe early results from a summer campaign that is sampling smoke above active fires in Utah and tracking how those plumes move through the atmosphere.
PyroCbs form when intense wildfire heat drives powerful upward motion. The resulting clouds can resemble thunderstorms, but their fuel is fire-generated heat and smoke rather than a conventional weather system. The largest events can produce lightning, hail and heavy rain while lofting particles and gases far above the surface.
Why these clouds matter beyond the fire
The immediate danger from a pyroCb is on the ground. Its strong updrafts can change fire behaviour quickly, create new ignitions through lightning and complicate decisions for crews and communities near a blaze. The atmospheric effects can last much longer. Once smoke reaches the upper troposphere or lower stratosphere, it can spread over large distances and remain aloft for months or, in some cases, years.
NASA's report notes that these smoke injections may influence the ozone layer and Earth's energy budget. That does not mean every wildfire produces a climate-scale atmospheric disturbance. PyroCbs are unusual, and their behaviour varies widely. The scientific challenge is to determine why only a small fraction of fires generate them, which fuels and weather conditions favour their formation, and how their impacts should be represented in forecast models.
A Utah fire provided an early sampling target
One of the campaign's first sampling flights took place on Aug. 3, when scientists followed a high-altitude smoke pulse from Utah's Widemouth 2 fire. Lightning started the fire on July 27. After remaining relatively small, it expanded rapidly on Aug. 2 during hot, dry and windy conditions and produced two pyroCb bursts that afternoon.
NASA's Aqua satellite captured the scene with the Moderate Resolution Imaging Spectroradiometer, or MODIS. In natural-colour imagery, the event appears as a tall chimney of smoke and cloud casting a shadow over lower smoke. A second processing method shows cloud-top brightness temperatures below minus 40 degrees Celsius, a commonly used threshold for identifying pyroCbs and for indicating that the cloud has reached the top of the troposphere or possibly entered the stratosphere.
The measurements also helped distinguish two separate pulses of pyroCb activity. That detail matters because repeated bursts can add complexity for fire forecasters and emergency officials dealing with a rapidly changing fire. A cloud that develops before sunrise is particularly unusual because it does not benefit from the daytime heating that normally helps drive convection. In this case, atmospheric instability and available water vapour appeared to support the event.
Aircraft observations fill a gap in the data
Satellites are essential for detecting pyroCbs across broad regions, but they cannot directly measure every property of the smoke plume. The INSPYRE campaign, short for INjected Smoke and PYRocumulonimbus Experiment, combines NASA's ER-2 aircraft, the NSF/NCAR Gulfstream V and ground-based sensors.
During the Utah operation, the Gulfstream V flew through smoke at roughly 12 kilometres above the surface. That altitude is not typically represented in the same detail in forecast models, so direct measurements can reveal how much material the plume carries, how its chemistry changes and how long the smoke remains concentrated. An accompanying aircraft photograph showed a precursor pyrocumulus cloud rising above the fire, with a bright, puffy top extending above darker smoke near the ground.
The campaign is not simply documenting dramatic clouds. It is building observations that can be compared with satellite data and atmospheric models. Better agreement between those systems could help researchers identify pyroCbs earlier and improve estimates of where their smoke will travel after the fire itself has changed.
A growing but incomplete record
Scientists have established that wildfires produce roughly 70 pyroCbs globally in a typical year, with many occurring in the forests of Canada and Russia. Grasslands and savannas can also generate them, and researchers had identified at least 13 in the continental United States during 2026 by the time of NASA's report. Those figures describe recognised events, not every wildfire with a tall smoke plume.
Researchers still do not know precisely why some fires create lightning-producing smoke storms while nearby fires do not. They are also working to determine which vegetation types are most likely to support pyroCb growth, why some clouds become more energetic than others and how reliably their development can be forecast.
NASA's Utah observations therefore represent an early piece of a broader evidence-gathering effort. The value of the campaign lies in connecting what satellites see from orbit with what instruments measure inside and around the plume. That combination can clarify how wildfire smoke moves into the upper atmosphere and provide a stronger scientific basis for assessing both immediate fire hazards and longer-lasting atmospheric effects.
