The Pioneer Fire in central Idaho produced another pyroCb cloud on 21 August 2016 (the first was on 19 August). GOES-14 was in SRSO-R mode, and sampled the fire with 1-minute imagery (above; also available as a large 73 Mbyte animated GIF) — a large smoke plume was evident on 0.63 µm Visible images as it moved eastward; large fire hot spots (red pixels) were seen on 3.9 µm Shortwave Infrared images; on 10.7 µm Infrared Window images, the cloud-top IR brightness temperature cooled to -35º C (darker green enhancement) between 2249-2307 UTC as it moved over Stanley Ranger Station (KSNY), not quite reaching the -40º C threshold to be classified as a pyroCb.
GOES-14 0.63 µm Visible (top), 3.9 µm Shortwave Infrared (middle) and 10.7 µm Infrared Window (bottom) images, with surface reports plotted in yellow [click to play MP4 animation]
However, a 1-km resolution NOAA-19 AVHRR 10.8 µm Infrared Window image (below; courtesy of René Servranckx) revealed a minimum cloud-top IR brightness temperature of -48.3º C (dark green color enhancement).
A larger-scale comparison of the NOAA-19 AVHRR visible, shortwave infrared and infrared window images is shown below.
NOAA-19 AVHRR 0.64 µm visible (top left), 3.7 µm shortwave IR (top right), 10.8 µm IR window (bottom left) and false-color RGB composite image (bottom right) [click to enlarge]
NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images [click to enlarge]