On 27 July a pyroCb formed from the Beaver Creek Fire in Colorado. GOES-15 detected the smoke plumes and pyroCu cloud, as well as the fire hot spot. The pyroCb (40.9º N, 106.6º W) formed around 21:30 UTC . Starting at 23:30 UTC on 27 July, the animation below (also available as an MP4) )shows GOES-15 (GOES-West) 0.63 µm visible (left) and 3.9 µm shortwave IR (right) . In the shortwave IR images, the red pixels indicate very hot IR brightness temperatures exhibited by the fire source regions.

GOES-15 0.63 µm visible channel (left) and 3.9 µm shortwave IR channel images (right) (click to play animation)
Since GOES-15 has a lower resolution the brightness temperatures appeared warmer.A 1-km resolution NOAA-18 image at 00:24 UTC on 28 July (below; courtesy of René Servranckx) showed the cloud-top IR brightness temperature of the pyroCb to be -40.4º C (green color enhancement).

NOAA-18 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).