Cottonwood Fire in Utah produces multiple pyrocumulonimbus clouds
1-minute Mesoscale Domain Sector GOES-18 (GOES-West) Infrared Window images combined with the FDCA Fire Mask derived product (above) showed that the Cottonwood Fire in southwestern Utah produced a sequence of pyrocumulonimbus (pyroCb) clouds beginning late in the day on 23 June 2026. These pyroCbs eventually drifted eastward across the Utah/Colorado border.
Each pyroCb exhibited cloud-top infrared brightness temperatures in the -40s C (shades of blue to cyan) — which is a necessary trait to be classified as a pyrocumulonimbus (since those temperatures assure that heterogeneous glaciation has occurred at the cloud top). With one of the final pyroCb clouds in the series, GLM Flash Points depicted a brief period of intermittent satellite-detected lightning activity (from 0613 UTC to 0629 UTC on 24 June).
1-minute GOES-18 Infrared Window + Fire Mask images that included plots of METAR surface reports (below) indicated that smoke from the Cottonwood Fire reduced the visibility to 3 miles at Hanksville, Utah (KHVE), Moab, Utah (KCNY, located midway between KHVE and KGJT) and even as far downstream as Grand Junction, Colorado (KGJT).
1-minute GOES-18 GeoColor RGB images with/without an overlay of Next Generation Fire System (NGFS) Fire Detection polygons (below) displayed the dense smoke plume that was emanating from the growing thermal signature of the Cottonwood Fire. This wildfire burned very hot, first exhibiting the 137.88ºC saturation temperature of GOES-18 ABI Shortwave Infrared (3.9 µm) detectors at 1719 UTC and maintaining that saturation infrared brightness temperature for the remainder of the time period shown below. The southeastern portion of Beaver County (where the Cottonwood Fire began) was experiencing Severe Drought conditions, which played a role in the rapid fire growth.
As of 24 June, the Cottonwood Fire became the most destructive on record for the state of Utah, with more than 100 properties damaged or destroyed.