Pyrocumulonimbus clouds produced by the Mullen Fire in Wyoming

September 19th, 2020 |

GOES-16 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.35 µm, bottom) images, with hourly plots of surface reports [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.35 µm, bottom) images, with hourly plots of surface reports [click to play animation | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed a series of pyrocumulonimbus (pyroCb) pulses emanating from the Mullen Fire in southeastern Wyoming on 19 September 2020. Each of the  pulses exhibited 10.35 µm brightness temperatures of -40ºC and colder  (shades of blue) — assuring the heterogeneous nucleation of all supercooled water droplets to form ice crystals, thereby meeting the criteria of a pyroCb.

The coldest cloud-top infrared brightness temperatures were around -47ºC, which corresponded to altitudes near 11 km according to rawinsonde data from Riverton, Wyoming (below).

Plot of 00 UTC rawinsonde data from Riverton, Wyoming [click to enlarge]

Plot of 00 UTC rawinsonde data from Riverton, Wyoming [click to enlarge]