NASA researchers sampled a wildfire cloud after an unexpected Idaho eruption

NASA said on Oct. 2 that its INSPYRE researchers had sampled a fire-generated cloud over the Wildhorse grass fire in eastern Idaho on Aug. 26. The unexpected encounter gave the team measurements of a smoke plume roughly an hour after it erupted, as scientists work to understand how such clouds affect fires and carry smoke high into the atmosphere.

The cloud was a pyrocumulonimbus, or pyroCb: a thunderstorm-like formation produced by an intense fire. NASA’s account describes the encounter as an opportunity to collect observations, not a completed finding about how much smoke reached the stratosphere or how the Idaho fire affected the climate.

How the Wildhorse fire changed an INSPYRE flight

The Gulfstream research jet was returning from a fire farther west when Sarah Woods, a National Center for Atmospheric Research scientist serving as a spotter, heard that Wildhorse had become unexpectedly intense. Dave Peterson, an INSPYRE co-principal investigator and Naval Research Laboratory meteorologist, told NASA the grass fire had initially seemed unlikely to be the main event.

As the aircraft neared the fire, Woods spotted the fresh remains of a pyroCb. Seeing the fire below helped confirm that the cloud had been generated by the blaze, NASA said. At her request, the pilots turned the aircraft and spent about three hours flying through the plume and the smoke trail drifting northwest toward Wyoming.

What NASA measured during the wildfire-cloud campaign

Over six weeks in summer 2026, researchers flew a Gulfstream jet based near Boulder, Colorado, while NASA’s high-flying ER-2 operated above fires across western North America. Ground crews carried sensors to observe events from below. The different vantage points let the team examine the clouds and smoke around them, from the fire’s vicinity to higher altitudes.

According to NASA, the Gulfstream collected smoke particles and gases, photographed ice crystals, and measured radiation passing through clouds or reflected toward space. The ER-2 carried 14 instruments to track fire intensity, updraft speeds, smoke and cloud properties from above. NASA’s airborne science campaign record lists 19 processed flights and 290 flight tracks, with further processing underway when the record was accessed.

PyroCbs can produce lightning and rain as well as strong winds that influence a fire below. NASA says the largest can lift smoke 30,000 to 50,000 feet, or roughly 10 to 15 kilometres, above the surface, potentially reaching the stratosphere. Those are characteristics of the phenomenon generally; NASA did not report a measured maximum altitude for the Wildhorse plume.

Why wildfire clouds matter beyond a fire line

Once smoke enters the stratosphere, it can travel across continents and persist much longer than smoke in the lower atmosphere, NASA says. Researchers want to determine how wildfire clouds lift smoke, how cloud processes alter its particles and gases, how much enters the stratosphere, and what happens afterward. The Idaho measurements are one part of that wider effort.

Earlier work shows why the question has attracted attention. A 2023 study by Katich and colleagues, published in Science and archived by NOAA, estimated from 13 years of airborne observations that pyroCbs account for 10% to 25% of black carbon and organic aerosols in the present-day lower stratosphere. That estimate predates INSPYRE and is not a result of the Wildhorse flight. The study described the wider effects of these rare, episodic events as uncertain.

On the ground, the question is more immediate. Neil Lareau, a University of Nevada, Reno atmospheric scientist who led INSPYRE’s ground observations, told NASA that a fire-generated storm can make its own wind. He hopes the research could eventually support warnings about downdrafts or wind shifts, giving fire managers time to move personnel. NASA has not reported that such a warning system has been produced by this campaign.

What the INSPYRE team still has to establish

Olga Kalashnikova, a NASA Jet Propulsion Laboratory researcher and INSPYRE principal investigator, said scientists still do not know whether pyroCb formation is driven chiefly by a fire’s energy, its intensity, or atmospheric conditions above it. Peterson said most numerical prediction models do not explicitly account for pyroCbs and their smoke injections. The campaign measurements are intended to give researchers data with which to test and improve those simulations.