Castle Fire pyrocumulonimbus cloud in California
1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed the formation of a pyrocumulonimbus (pyroCb) cloud that was spawned by the Castle Fire in California on 23 August 2020.The coldest pyroCb cloud-top infrared brightness temperatures were around -50ºC –according to 00 UTC rawinsonde data from Las Vegas, Nevada (below) indicated that this temperature corresponded to altitudes around 12 km.