Scientists with NASA's INSPYRE (INjected Smoke and PYRocumulonimbus Experiment) campaign have been actively hunting pyrocumulonimbus clouds (pyroCbs) across western North America. This elusive weather phenomenon, generated by intense wildfires, has become a key focus for researchers aiming to understand its atmospheric impacts.

PyroCbs are formed when a powerful fire creates an intense chimney of smoke, funnelling it upwards. The largest of these clouds can propel smoke to altitudes of 30,000 to 50,000 feet (10 to 15 kilometres), reaching the cruising heights of commercial aircraft and even penetrating the stratosphere. Once in the stratosphere, the smoke can spread across continents, circulate the globe, and persist for significantly longer periods than it would in the lower atmosphere.

These fire-driven clouds are not merely smoke plumes; they are capable of generating their own weather. Rising above intense fires, pyroCbs can produce lightning and rain. Concurrently, they can unleash powerful winds that have the potential to whip the flames below into a greater fury, exacerbating the wildfire itself.

The significance of pyroCbs as a distinct atmospheric phenomenon became apparent around the turn of the 21st century. Satellite observations from that period began to reveal smoke plumes reaching altitudes previously associated only with major volcanic eruptions, highlighting the profound atmospheric reach of these fire-induced clouds. This discovery underscored the need for dedicated research into their formation and effects.

The INSPYRE campaign has observed specific instances of pyroCb formation, including the Wildhorse grass fire in eastern Idaho, which unexpectedly erupted with a massive pulse of smoke, initiating a pyroCb. Another event, the Widemouth 2 fire in Utah, was observed from a research jet on August 3 as part of the campaign's efforts. These observations are crucial for gathering data on the dynamics and characteristics of these powerful and far-reaching fire-spawned weather systems.