The Wildfire That Built Its Own Thunderstorm
A research plane caught the aftermath of an unexpected fire-born thundercloud over Idaho. The new measurements may reveal how smoke escapes into the upper atmosphere.
The Discovery
A grass fire in eastern Idaho did something the researchers had not planned for: on August 26, it produced a pyrocumulonimbus cloud, a thunderstorm powered by fire. NASA’s October 2 report says a Gulfstream research aircraft returning from another fire reached the Wildhorse plume and spent about three hours sampling its smoke trail. The team encountered the plume roughly an hour after the cloud erupted, not at the instant it formed.
The encounter was part of INSPYRE, a six-week aircraft campaign pairing flights with high-altitude, ground and satellite observations. Researchers gathered smoke particles, gases, cloud measurements and radiation data. Those measurements have not yet settled what triggered this particular cloud.
What Makes It Strange
An intense fire can make its own weather. A pyrocumulonimbus can produce lightning and shifting winds, then loft smoke as high as aircraft cruise or even into the stratosphere. NASA says scientists still do not know how much depends on fire intensity versus atmospheric conditions overhead.
- Observed: an unexpected fire-driven cloud and a sampled aftermath over Wildhorse.
- Known mechanism: powerful updrafts can carry smoke far above a normal surface plume.
- Unresolved: how the sampled particles change in clouds and how much smoke reaches the stratosphere.
The Implications
Once smoke reaches that upper layer, it can linger and travel farther than lower-atmosphere smoke. The team will combine aircraft measurements with satellites and models to investigate weather and climate effects. A future forecast warning firefighters of cloud-driven wind shifts is an aim, not a warning system already proven by this campaign.
The fire was on the ground. Its weather did not stay there.