Another Pioneer Fire pyroCb in Idaho

GOES-15 Visible (0.63 µm, top), Shortwave Infrared (3.9 µm, middle) and Infrared Window (10.7 µm, bottom) images [click to play animation]

The Pioneer Fire in central Idaho produced another pyroCb cloud on 29 August 2016. GOES-15 (GOES-West) Visible (0.63 µm), Shortwave Infrared (3.9 µm) and Infrared Window (10.7 µm) images (above; also available as an MP4 animation) showed the development of the pyroCb, which exhibited a minimum cloud-top IR brightness temperature value of -56º C (darker orange color enhancement) at 0230 UTC on 30 August as it drifted east-northeastward over the Idaho/Montana border. This temperature corresponded to an altitude of 11.7 km (218 hPa) on the nearby Boise ID sounding (below).

Boise, Idaho rawinsonde report [click to enlarge]

1-km resolution POES AVHRR images (below; courtesy of René Servranckx) showed pyroCb cloud-top IR brightness temperatures as cold as -66.7º C at 0044 UTC and -60.4º C at 0122 UTC.

POES AVHRR Visible (upper left), Shortwave Infrared (upper right), Infrared Window (lower left) and false-color RGB (lower right) images [click to enlarge]

POES AVHRR Visible (upper left), Shortwave Infrared (upper right), Infrared Window (lower left) and false-color RGB (lower right) images [click o enlarge]

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