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]

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]

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 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]

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

Another PyroCb in Idaho

On 24 August a pyroCb formed  from the Henry Creek Fire in Idaho. GOES-15 detected the smoke plumes and pyroCb cloud, as well as the fire hot spot. The pyroCb (43.4º N, 111.7º W) formed around 23:45 UTC .  Starting at 23:00 UTC on 24 August, 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)

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 00:02 UTC on 25 August (below; courtesy of René Servranckx) showed the cloud-top IR brightness temperature of the pyroCb to be -41.5º 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).

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).

A second pyroCb in Idaho

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

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]

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.

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).

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 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]

A larger-scale comparison of the NOAA-19 AVHRR visible, shortwave infrared and infrared window images is shown below.

NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images [click to enlarge]

NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images [click to enlarge]

PyroCb in Idaho

A small pyroCb cloud developed from the Pioneer Fire in Idaho during the evening hours on 19 August 2016, which difted quickly to the southwest; GOES-15 (GOES-West) 0.63 µm Visible and 3.9 µm Shortwave Infrared images (below) showed the fire hot spot (red pixels on the 3.9 µm images) and the pyroCb plume in the visible. Since the pyroCb occurred near sunset there is not a lot of visible imagery to show the southwestward  progression of the pyroCb cloud (which would have placed the cloud between the 415-320 mb or 7.3-9.1 km altitude, according to winds from the Boise ID sounding).

GOES-15 0.63 µm visible channel (left) and 3.9 µm shortwave IR channel images (right) (click to play animation)

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 Infrared channel resolution (4 km), the pyroCb cloud-top IR brightness temperatures appeared warmer than the -40º C threshold for classification as a pyroCb. However, a 1-km resolution NOAA-18 image at 1:11 UTC on 19 August (below; courtesy of René Servranckx) showed the coldest cloud-top IR brightness temperature of the pyroCb to be -49.1º C (yellow color enhancement), or between 10.8-11.5 km according to the Boise sounding data.

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).

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).

In addition, AVHRR 12 µm imagery shows the pyroCb reaching -52º C (yellow color enhancement).

AVHRR 12.0 µm IR image

AVHRR 12.0 µm IR image

PyroCb in Wyoming

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

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

A pyroCb cloud developed from the Maple Fire in far northwestern Wyoming during the late afternoon hours on 15 August 2016; GOES-15 (GOES-West) 0.63 µm Visible, 3.9 µm Shortwave Infrared and 10.7 µm Infrared Window images (above; also available as an MP4) showed the fire hot spot (red pixels on the 3.9 µm images) and the pyroCb cloud (shades of green to yellow on the 10.7 µm images) as it drifted southward then southwestward over far eastern Idaho by 0200 UTC on 16 August.

After sunset, GOES-15 3.9 µm Shortwave Infrared and 10.7 µm Infrared Window images (below; also available as an MP4) showed a gradual decrease in the intensity and areal coverage of the 3.9 µm fire hot spot, along with a continued cooling trend of the 10.7 µm pyroCb cloud-top IR brightness temperatures (which reached -49º C at 0341 and 0345 UTC).

GOES-15 Shortwave Infrared (top) and Infrared Window (bottom) images [click to play animation]

GOES-15 Shortwave Infrared (top) and Infrared Window (bottom) images [click to play animation]

A 4-panel composite of NOAA-18 images at 0146 UTC on 16 August (below; courtesy of Rene Servranckx) depicted a minimum cloud-top IR brightness temperature of -55.5º C, which corresponds to an altitude of 11.5 km according to the 00 UTC Riverton, Wyoming rawinsonde data.

NOAA-18 Visible (upper left), Shortwave Infrared (upper right), Infrared Window (lower left) and false-color RGB composite (lower right) images [click to enlarge]

NOAA-18 Visible (upper left), Shortwave Infrared (upper right), Infrared Window (lower left) and false-color RGB composite (lower right) images [click to enlarge]

PyroCb in Colorado

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)

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).

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).