Utah Wildfire Unleashed PyroCb: Smoke particles directly measured in stratosphere

The INSPYRE mission has captured direct measurements of smoke particles and gases injected into the stratosphere during the Widemouth 2 wildfire in Utah. The multi-platform campaign combined satellite remote sensing, high-altitude aircraft sampling, and ground-based sensors to observe two distinct pyrocumulonimbus (pyroCb) events — towering fire-driven thunderstorms whose tops pierced the tropopause.

Campaign design and observational platforms

The research team coordinated four instrument systems. NASA's Aqua satellite carried the Moderate Resolution Imaging Spectroradiometer (MODIS), which detected two separate pyroCb pulses by recording cloud-top temperatures below –40 °C — a threshold indicating that the convective columns had reached the upper troposphere and crossed into the stratosphere. The ER-2 high-altitude aircraft and the NSF/NCAR GV research aircraft provided in-situ sampling capability, while ground-based sensors supplied continuous surface and boundary-layer context.

Direct stratospheric sampling

A GV flight on August 3, 2026, flew directly into the smoke plume at approximately 12 kilometers altitude. The crew collected air samples inside the plume, obtaining composition data from a level that operational weather prediction models do not routinely assimilate. The researchers emphasize that such in-plume measurements at tropopause-penetrating altitudes are rare and fill a specific observational gap.

Climate-relevant emissions

The campaign's results feed into an emerging quantitative picture. Scientists involved in the analysis estimate that wildfires may contribute up to 25 percent of the black carbon and organic aerosols found in the lower stratosphere — a magnitude comparable to the stratospheric perturbation from major volcanic eruptions. PyroCb clouds also generate lightning, hail, and intense rainfall, compounding immediate hazards for fire management and evacuation operations.

Interpretive boundaries and open questions

The dataset does not resolve several fundamental drivers. The team has not yet determined which vegetation types most reliably trigger pyroCb formation, why some pyroCb clouds produce substantially more lightning than others, or how to forecast pyroCb occurrence with high accuracy. These gaps remain explicit targets for subsequent analysis of the INSPYRE observations and for future campaign planning.

Source: This article was adapted from an original Russian-language publication by Pravda.Ru.